TheL1nds says FML
Today, I checked my fake Facebook account for the first time in ages and realized that the fake me got more birthday greetings than the real me. FML
from FMyLife http://bit.ly/Kc4s8i
Today, I checked my fake Facebook account for the first time in ages and realized that the fake me got more birthday greetings than the real me. FML
from FMyLife http://bit.ly/Kc4s8i
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“Mobile Web design.” Unless you’ve been hiding under a bush for the last 18 months, you’ll know that it’s one of the hottest topics in the industry at the moment. Barely a week goes by without new tips being unveiled to help us hone our skills in making websites work as well — and as fast — as possible on mobile devices.
If you own or have designed a WordPress website for the desktop and are considering going mobile, the process can be fairly daunting. You probably know of responsive design and might have heard of the mobile-first approach developed by Luke Wroblewski, which entails planning the content and design for mobile devices first and then desktops second, rather than the other way round.
But if your WordPress website has a desktop theme in which everything is set in pixels, then the thought of adopting a responsive design might have you running for the hills.
It doesn’t have to be that way.
Here are four ways to make your WordPress blog or website mobile-friendly, ranging from the quick and dirty to the complex but potentially very beautiful. As well as outlining the pros and cons of these methods, we’ll include information on plugins that will help without actually doing all the work for you, and we’ll provide some code that you can use for a responsive design.
Designing for content is increasingly becoming more common than squeezing content into a pixel-perfect design, as documented here on Smashing Magazine.
If your website is more about content than design (say you run a blog that is content-heavy and designed for reading), then you won’t be too fussed about what your website looks like on mobile devices. You just want people to be able to read it without having to zoom in, move the viewport around or generally tie themselves up in knots until they decide to leave.
If this is the case, then a simple plugin might do the trick. Below are some plugins to consider.
WPtouch, which comes in free and premium versions, strips out your existing theme and displays your content and not much else, but the result is user-friendly, robust and easy to read.
WPtouch is widely used on websites, including Stephen Fry’s blog and Social Media Examiner. You can see below how the plugin renders those two websites. The premium version has options to modify the colors and some styles, including a bespoke menu at the bottom of the screen, as seen on Social Media Examiner.
Social Media Examiner desktop design
Social Media Examiner mobile design, using WPtouch
The WordPress Mobile Pack has some color options and can be used as a mobile switcher if you want a completely different theme for mobile devices. It also has a mobile interface for editing posts, although this has been superseded to some extent by the WordPress apps for iOS and Android.
WordPress Mobile Pack screenshots
If your website runs BuddyPress, then you’ll need a plugin to ensure that none of its functionality is lost on mobile devices. BuddyPress Mobile has theming options, and you can edit the style sheet to make the mobile design your own.
If you want a consistent design across desktop and mobile, but you don’t yet have a theme or you want to develop one, then a mobile theme might be the answer.
More and more mobile themes have sprung up over the last year. In particular, Twenty Eleven, WordPress’ default theme since version 3.0, is responsive enough for many websites.
Below are some other themes that include a mobile or responsive style sheet.
The Carrington family of themes can be used as parent themes. You can edit the CSS and functions to suit your needs, and it has a mobile version.
Scherzo is clean and minimalist and would be great to use as a parent theme. It uses a mobile-first responsive design.
E-commerce websites are trickier to make mobile-friendly, but Jigoshop can help. It’s a full e-commerce plugin and theme, with a responsive layout that can be tweaked to suit your design.
In the days before responsive design gained traction, websites commonly had two versions: desktop and mobile. The mobile version might have been on an m. subdomain or have a .mobi extension. Some websites out there still do this, mainly huge news websites that serve different content depending on the device.
Fewer WordPress administrators are choosing to do this now, but if you do want to go down this route, then serving two versions of your website from the same database is possible, by using a mobile switcher.
Here are two plugins that make this possible:
Using one of these plugins enables you to develop a completely separate theme for mobile devices, with its own layout, navigation and content structure.
If you don’t want to throw out your existing theme, then the best way to give mobile users an experience that is at least visually similar to the desktop version is to build responsiveness into your theme.
A responsive theme contains media queries in the theme’s style sheet to define CSS that applies only to devices of a specified maximum or minimum width. A truly responsive theme has a fluid layout that adapts to mobile devices and larger screens to some extent already, but with some extra styling to make the layout optimal for mobile devices.
To get started, you will need to define media queries in the style sheet. Most of the styles already in your style sheet apply to desktop and mobile, so you only need to add CSS that is different for mobile devices. This will go at the end of your theme’s style sheet.
Start by defining the screen width you are developing for. There are two main approaches to this:
A media query consists of three main parts:
@media rule;print and screen — we’ll use screen);You could have a media query to target mobile phones (and other small devices such as the iPod Touch) in portrait orientation that have a width of 320 pixels:
@media screen and (max-width: 320px) {
}
The CSS to be applied to that screen width and any screen narrower than it would be written between the braces.
An alternative to the @media rule would be to create a linked style sheet with the CSS for each screen width. But I don’t do that because it adds another server request with the potential to slow the website down; and managing all of the styles becomes harder if they’re in more than one place.
Here are other media queries for commonly targeted screen sizes:
(max-width: 480px)(max-width: 780px)(max-width: 1024px)You can run one media query after another so that each change you make applies to the screen size you’re querying, plus any widths queried further down in the style sheet. In this case, you would work with wider screens first. For example:
@media screen and (max-width: 480px) {
}
If you are ignoring tablets, you would include this media query first and add any CSS for mobile phones in both portrait and landscape modes (for example, any changes to graphics or text size). You would then follow it with this:
@media screen and (max-width: 320px) {
}
Here, we’re adding any styles that apply only to phones in portrait mode (such as layout changes). You don’t need to repeat the CSS that applies to both landscape and portrait modes because this will still apply. In the same way, you don’t need to repeat any styles that will stay the same for desktop views because they will cascade down from the earlier parts of the style sheet.
Phew! So, now we’ve defined media queries, and we’re ready to roll with some mobile-friendly CSS. Below are the main things you will need to work on for a standard WordPress website. Let’s assume your website’s markup is similar to that of the Twenty Eleven theme (i.e. html → body → header (or div #header) → #main → #content → #primary → #secondary → footer (or div #footer). You might need to substitute your own elements and IDs for the ones in the examples below.
Overall width of website
You’ll need to change this so that it displays correctly. Add the following code between the braces of your first media query:
body {
width: 100%;
float: none;
}
This ensures that the website’s body fills the width of the device and removes any floats. At this point, you might also want to change the background image if there is one (more on that shortly).
You will now have the following code at the bottom of your style sheet:
@media screen and (max-width: 480px) {
body {
width: 100%;
float: none;
}
}
Width of content and sidebar
In portrait mode in particular, there isn’t room for a sidebar to the right of the main content. Add the following code to the media query relating to devices with a maximum width of 320 pixels:
#content, #primary, #secondary {
width: 100%;
float: none;
margin: 10px 0;
}
Footer content, especially widgets
If your footer has widget areas or other elements with floats applied, you will need to override them for mobile devices in portrait mode.
If you want the footer widgets to be full width in both landscape and portrait modes, then simply add footer.widget-area to the CSS for the sidebars and content.
However, you might want the widget areas to be laid out side by side in landscape mode, depending on how many you have. In that case, you’ll need to do the following:
footer .widget-area {
width: 100%;
float: none;
margin: 10px 0;
}
You might also need to adjust the text alignment and borders and padding, depending on your existing theme. Margins should be set to 0 on the left and right; suit them to your theme at the top and bottom, but generally they should be smaller than in the desktop version.
Image sizes
The images in your design might still break the layout or break out of their containing elements, making your website shrink when viewed on a mobile device. There is an easy fix for this:
body img {
max-width: 100%;
}
This will ensure that images are never wider than their containing element. You might need to tweak the CSS if images sized further up in the style sheet have greater specificity.
However, this solution isn’t ideal. The images might look smaller, but mobile devices will still have to download their full sizes, which will slow down response times and possibly lose visitors, as well as annoy users on expensive data plans (more of them are out there than you might think). There a number of solutions to this, some of which you will find in this roundup of articles on responsive images. You may recall the mobile-first approach mentioned earlier; one benefit of this approach is that it serves different-sized image files to devices based on screen width.
Text size
So, our layout is working, and everything displays nicely. But now that the website is narrower, the text might appear huge. We’ll need to adjust the text’s size with the following code:
body {
font-size: 60%;
line-height: 1.4em;
}
This sets the font size as a percentage of the size set for it further up in the style sheet.
Sometimes mobile users will want to access specific content; for example, visitors to a store’s website will want to find the store’s location easily, and visitors to an e-commerce website will want to shop with a minimum of clicks (or taps). Sometimes you might want to adjust the navigation to make the website look more like an app.
Here are some methods you can follow to do this:
The possibilities are limited only by your imagination and creativity!
You’ve added the media queries above, but your smartphone still displays the desktop version. Don’t worry! This is because many smartphones use a virtual viewport that is equal to the width of a small desktop, which prevents desktop-designed websites from breaking when rendered in the browser. This can be easily fixed by placing the following code in the head of each page. Because yours is a WordPress website, you need to add it only once, to the header.php theme file:
<meta name=”viewport” content=”width=device-width”>
What this does is tell the phone to treat the size of the screen as its actual size, not the virtual size… if that makes sense.
Here’s what we’ve looked at in this article:
As you can see, no one option is necessarily the best; it will depend on the website, on the budget and on the time and capability of those involved. Over time, most mobile-friendly WordPress websites will have responsiveness built into them, instead of using a separate theme, mobile website or plugin.
Hopefully this article has given you a starting point to make your WordPress website mobile-friendly. This is just the beginning of the possibilities. To further develop your mobile website, you might want to consider a mobile content strategy; a mobile-first design; APIs and native device functionality to create an even more app-like experience; and more.
Enjoy!
(al)
© Rachel McCollin for Smashing Magazine, 2012.
Ruby is an object-oriented language. What does that even mean? It has unique quirks and characteristics that we’ll explain clearly. This article assumes that you have no programming experience, not even HTML.
An important skill to have when creating a program is translating — translating the desires of the user into the output they are looking for. In order to do that, you have to be able to think like a developer so that you can take what you know instinctively (as a user) and morph it into what the computer needs to be able to do what you want. So, we’ll help you start thinking like a developer. When you are done, you should have a mental model of how Ruby works and be on your way to becoming a successful Rubyista.
We’ll take you through a variety of the fundamental elements of the Ruby language and explain the whys behind the hows.
For all the code samples we go over, you can test them out on Try Ruby (without having to install anything on your computer). You can follow Try Ruby’s tutorial if you want, but you don’t need to in order to understand what we’ll outline below. It’s just a quick way to get your feet wet without the headache of installing anything.
The interpreter for Ruby — basically, the main brain of the programming language that makes sense of the code you write — reads the code from top to bottom and left to right; meaning, it starts at line 1, character 1, literally, and first reads across line 1 to the last character, then goes down to the next line, and repeats this process until it reaches the last line of your program. If you have any syntax errors — i.e. errors in your code, such as misspelled variable names, improper use of constants (we’ll get to constants in a bit), etc. — it will halt execution and show you an error message, usually with a line number corresponding to the code. Remembering this is important because if you encounter an error report while coding, you will need to know how to decipher it. Figuring this out isn’t always straightforward for beginners.
Fictitious code from The Matrix. (Image: Absolute Chaos)
This top-down parsing also affects the control of the flow of logic in your program. Say you want to calculate the balance of someone’s account before showing it to them. You would have to make sure that you put the method and function that does the calculation before the output of the balance; that is, if you are outputting the balance at line 10, then you would have to do the calculations somewhere between line 1 and 9. We’ll dive into this later.
An object is a thing. It is at the heart of Ruby. Going back to our earlier statement about Ruby being an object-oriented language, that means that Ruby manipulates all data on the assumption that the data is an object. There are many object-oriented languages, but very few put the object at the center of their universe like Ruby does. In Ruby, everything is an object. I mean everything: every variable, every operation. Every object has different characteristics; that’s what makes them different. A string is an object that has built-in characteristics that make it suitable for handling text. For a more technical definition, check out the article “Object” on Wikipedia.
A method is simply a definition of an action that can be performed on an object. Ruby has built-in object definitions and methods. One such method is capitalize for the Ruby class strings (we will dive into strings later).
string1 = "this string is awesome"
If you wrote string1.capitalize, the output would look something like this:
"This string is awesome".
All that the capitalize method tells the Ruby interpreter to do is convert the first character of the string from lowercase to uppercase. Check out an example directly from the Ruby documentation. As you can see from the documentation, the string object in Ruby has a ton of methods that you can use right out of the box.
Another thing you should have noticed is the way to call a method, string1.capitalize, which is basically <object name> . <method name>.
In this case, the object is a string variable. If you tried to do capitalize on an object that is not a string, Ruby would throw an error.
You can create any method for any of your objects. Here is the way to do that:
def method_name #Enter code here end
The # basically tells the Ruby interpreter that this is a comment for another human and to ignore it. So, the Ruby interpreter skips lines that begin with a #.
A class is like a blueprint that allows you to create objects of a particular type and to create methods that relate to those objects. But classes have a special property called “inheritance.” Inheritance means just what you would think. When you inherit something from someone, it likely means a few things:
Classes are like a blueprint for objects. (Image: Todd Ehlers)
Those principles are the same in Ruby. There are parent, grandparent and children classes. As a general rule, children classes inherit all of the attributes of a parent or grandparent class.
In Ruby, an object’s grandparent class is known as its “superclass.” In other words, if you have an object that is a string — meaning that your object inherits the properties of the String class — then the parent class of String is String’s superclass. Be careful not to miss an important distinction here: the superclass of String (which is a class that tells Ruby how to treat strings) is not the same as the superclass of a String object. Here is a demonstration:
> num1 = "this is a string" => "this is a string" > num1.class => String > String.superclass => Object > Object.superclass => BasicObject > BasicObject.superclass => nil
What we have done is set the local variables num1 to be a string. When we check the class of num1, by calling the .class method, it tells us that the class of num1 is String. Then, when we checked the superclass of String, it tells us Object, and so on.
Look at what would happen if we tried num1.superclass:
> num1 = "this is a string" => "this is a string" > num1.superclass => #<NoMethodError: undefined method `superclass' for "this is a string":String>
The reason this doesn’t work is because num1 is an object (a local variable) that has inherited the properties of the class String. And num1 is not a class, so it has no superclass.
Here is another way to do what we did earlier:
> num1 = "this is a string" => "this is a string" > num1.class => String > num1.class.superclass => Object > num1.class.superclass.superclass => BasicObject > num1.class.superclass.superclass.superclass => nil
The reason the last value is nil is because BasicObject has no parent. It inherits nothing from another class, so it stops there.
One key thing we have done here that is different from before is we have “chained” methods, meaning we have continued applying a method to the current statement. That’s another beautiful thing about Ruby: every time it evaluates something, it returns a copy and allows you to continue evaluating it.
Take the last line:
> num1.class.superclass.superclass.superclass => nil
Basically, Ruby did this:
num1? It’s a string, so return String.String? String is a child class of Object, so return Object.Object? Object is a child class of BasicObject, so return BasicObject.BasicObject? BasicObject is not a child class of anything, so return nil.All on one line, all in one command. Simple, neat, elegant.
The structure of classes and superclasses is the hierarchy of class inheritance.
Now the question is, how do you define a class and use one? Glad you asked.
class MyClass # some code logic end
That’s it.
Basically, you just have the opening keyword, class, followed by the name of your class (MyClass, in this case). Then you have some code. And when you are done, you close it with the keyword end. Make sure that class and end are always all lowercase (i.e. don’t write Class or End or you might get errors).
That’s all there is to it.
If you have a parent class that you want this new class to inherit stuff from, you would define it like this:
class MyChildClass < MyClass # some code that is specific to the child class end
Ruby interprets the < operator to mean that the class name on the right side is the parent and the class name on the left is the child (therefore, the child should inherit methods and such from the parent).
Also, remember that class names usually start with an uppercase letter; and if their name has multiple words, you do what is called “CamelCasing” — i.e. instead of using a space or underscore or hyphen, you just start the new word with an uppercase letter.
Now we know how to create a class, which we know is the blueprint of an object type. So, if you think of baking, a class is like a recipe (which contains a list of ingredients and instructions for creating something). But once you create something — say, blueberry muffins — then each muffin may be considered an “instance” of that class.
So, each instance or muffin is an object.
The way to create an instance is like this:
muffin = BlueberryMuffin.new
That’s it.
To be technical, the only part of the statement above that actually creates an instance of the BlueberryMuffin class is BlueberryMuffin.new. In order to use the object, you have to store it somewhere, so we’ve stored it in the local variable muffin so that we can reuse this specific instance (or muffin).
You will need to do more technical things with a class, like set up an initialization method so that whenever you create an object of the class, Ruby knows how to do that exactly. That is a bit beyond the scope of this article — just understand what a class is, how it relates to objects, how to create new objects, etc.
To read up on classes, check out the article about them on Learn Ruby The Hard Way.
How is data structured?
At the core of programming is the manipulation of data. Computer scientists have come up with a way to manipulate data in a structured way by inventing things called “data structures.” A data structure is simply a container for a particular type of data. Words are handled differently than formulas; likewise, characters and letters are handled differently than numbers — in most cases.
What’s a variable?
A variable is the name of the most basic type of container that you will store data in. Each variable name has to be unique to its scope (i.e. the area in which the variable is allowed to exist). Think of it as a Venn diagram, in which each variable is only valuable in the circle or square within which it is contained.
Say you wanted to create a program (or a part of a program) that is responsible for adding two numbers. From the coder’s point of view, you would need to set up a container for each of those numbers, and then set up the mathematical function between the containers. The reason to do this is because you don’t want the user to have to edit the source code every single time they want to calculate the sum. Although you could do that, the solution is neither practical nor efficient. Most users know what a calculator looks like, so they can just press the buttons or enter the numbers. But editing source code is a no-no.
In Ruby, each of those containers is a variable. So, you would do something like this:
sum = num1 + num2
As opposed to something like this:
sum = 19 + 20
Ruby and many other languages have many types of variables. We’ll go over just a few to be brief and not confuse you too much.
num1 — that is used in three different ways in each of those methods and that stores three different values. Going back to the Venn diagram, suppose there are three shapes within the diagram: Circle 1, Circle 2, Square. Also suppose that Circle 1 and Circle 2 are not connected, but both are within Square. A local variable would be confined to its respective circle and would not be able to affect anything outside of its circle. The way to use these variables is to just use them. If you want to use a local variable called sum that stores the sum of the values of num1 and num2, you would simply write sum = num1 + num2.$ before the name. So, suppose you want to calculate multiple dimensions of a circle, and you want to define the radius beforehand. You would do something like this: $radius = 20. Then, at any other time throughout the program, regardless of whether you are in a subcircle of the square or in the square alone, you can reference $radius. Now, using global variables has a good side and bad side. The good side is that you can read the value of a global variable in any method or function within your program. The bad side is that you can also write to a global variable in any method or function within your program. If you change the value, forgetting that another method or function depends on the previous value could really screw things up. As a rule, then, stay away from global variables unless you are confident that you know where they will be used and how changes would affect the rest of the program.PI = 3.14. Constants have to begin with an uppercase letter, and more often than not they are all uppercase, but they don’t have to be. Note that I said that the values of constants are supposed to be constant throughout your entire program, but they can be changed. Ruby doesn’t forbid you from changing the value, but when you do, it gives you a warning because it doesn’t like it. Going back to the Venn diagram, think of PI as being set outside of the square, and it can be used anywhere within the square and anywhere within the circles within the square.@@ at the beginning of the name of the variable.@ at the beginning of the name of the variable.Here’s a recap on how to use the variable types:
sum = num1 + num2$radius = 20$.PI = 3.14@@length = 10 #Square, and defined the length of each side for demonstration purposes. What’s important to note here is that all “squares” would have a “length” of 10 by default.@length = 5 #5 instead of the default 10. You could use this instance variable to specify the length of this particular square, your “Red Square.”Note that these rules are by no means comprehensive. Some words you can’t use as variable names. They are called “reserved words,” which Ruby uses internally to identify various elements of the language.
To find out more about variables and other do’s and don’ts, check out the following resources:
What is a string?
A string is a series or sequence of characters — i.e. a “word” or sequence of words. You might say a sentence, but a string is not just a sentence. For instance:
string1 = 'a' string2 = 'This is a string'
Two things are happening here. The first is that we are using local variables, and the second thing is that we are using single quotes to define the content of the variable. Even though string1 contains just one letter, it is still a string because it is declared in single quotes. Ruby knows how to treat a variable by the way it is declared. You can use double quotes, but you have to be consistent. You can’t start the string’s declaration with a double quote and end with a single quote, like this: string1 = "This is a string'. But you can do this: string1 = "This is a string", or string2 = 'This too is a string'. Both are valid, and it’s just a matter of taste.
num1 = 9
This sets num1 to the numerical value of 9. So, if you did num1 + 1, the result would be 10.
But if you used single quotes around the 9, like this…
num1 = '9'
… then that would say that 9 is actually a string, not a number. So, if you wrote num1 + 1, it would throw an error along the lines of: => #<TypeError: can’t convert Fixnum into String>. The Ruby interpreter is basically saying that you have given it a number and a string and that it doesn’t know how to add them.
To take that one step further, if you did this…
num1 = '9' num2 = '1' num1 + num2
… the result would be this:
"91"
Because Ruby would take the two strings and literally squish them together. When you specify a value in quotes (either single and double quotes), you are telling the Ruby interpreter, “Don’t translate this. Just take the exact content between the beginning and end quotes.” It treats the 9 like any other letter. So, as far as Ruby is concerned…
num1 = '9'
… is more or less the same as this:
num2 = 'a'
As a matter of fact, if you did num1 + num2, the result would be 9a.
In summary, a string is just a combination of letters, numbers and special characters.
So far, we have covered individual pieces of data, such as one or a handful of items that can be stored in a local variable, or a single object created as an instance of a class.
But what happens if we want to work with many pieces of data — that is, a collection, such as a series of numbers that we need to put in ascending order, or a list of names sorted alphabetically. How does Ruby manage that?
Ruby gives us two tools: hashes and arrays.
The easiest way to explain an array is to show an image of what a “typical” one looks like.
Rather than having six different variables for the six food types, we have just one food array that stores each food item in its own container or element. The numbers to the right of the diagram above are the “index” or “keys” (i.e. addresses) of each element ([0] = chicken, [1] = rice, etc). Note that the keys are always integers (whole numbers) and always start at 0 and go up from there. So, the first element is always [0], and [1] is always the second element, etc. So, you will know that the range of keys of any array is always [0] to (length-1) — meaning that the last element is always total length of the array minus 1, because we started at [0].
To create the above in Ruby, we would do something like this:
food = ['chicken', 'rice', 'steak', 'fish', 'shrimp', 'beef'] => ['chicken', 'rice', 'steak', 'fish', 'shrimp', 'beef'] > food.count => 6
Notice that for each element, we use single quotes (we could have used double quotes instead) because we are storing strings in each element. Ruby’s array class has some methods that we can use right out of the box, such as count, as used above. It simply counts the total number of elements in the array and outputs that value. Thus, even though the index goes up to 5, there are 6 elements because the index started at 0.
Now that we have created a food array, we can access each item by invoking the name of the array that we created, followed by the index number.
> food[0] => "chicken" > food[1] => "rice" > food[2] => "steak" > food[6] => nil
The reason we get nil at food[6] is because there is no [6] — or, rather, nothing is stored in food[6], so Ruby automagically sets food[6], food[7], food[8] and so on to nil. To add another food item to this array, all you would have to do is set the next element to whatever value you wanted, like so:
> food[6] = 'carrots' => "carrots" > food => ["chicken", "rice", "steak", "fish", "shrimp", "beef", "carrots"] > food.count => 7
There is another way to add elements to your array in Ruby. You use the append operator, <<, which basically sticks something at the end of the array. The difference here is that we don’t have to specify an index position when using the append operator. We just do this:
> food << "irish potato" => ["chicken", "rice", "steak", "fish", "shrimp", "beef", "carrots", "irish potato"] > food << 42 => ["chicken", "rice", "steak", "fish", "shrimp", "beef", "carrots", "irish potato", 42]
Everything that comes after the << is added to the array. This is pretty convenient because you can append variables and other objects to an array without worrying about the content itself. For instance:
> sum = 10 + 23 => 33 > food << sum => ["chicken", "rice", "steak", "fish", "shrimp", "beef", "carrots", "irish potato", 42, 33]
All we did here was create a local variable named sum, and then push the value of sum to the end of the array. We can even add arrays to the end of other arrays:
> name_and_age = ["Marc", "Gayle", 28] => ["Marc", "Gayle", 28] > food => ["chicken", "rice", "steak", "fish", "shrimp", "beef", "carrots", "irish potato", 42, 33] > food.count => 10 > food << name_and_age => ["chicken", "rice", "steak", "fish", "shrimp", "beef", "carrots", "irish potato", 42, 33, ["Marc", "Gayle", 28]] > food.last => ["Marc", "Gayle", 28] > food.count => 11
Even though the last element is an array with three elements — Marc, Gayle, 28 — it still counts as just one element (i.e. one array) inside the food array. So, the count figure goes from 10 (before name_and_age is added) to 11.
If we wanted to find out how many elements were inside the last element of the food array, we could do something like this:
> food.last.count => 3
A few other interesting methods that Ruby allows us to use right out of the box are first, last, length, include? (followed by the object you want to check for), empty?, eql? and sort.
> food
=> ["chicken", "rice", "steak", "fish", "shrimp", "beef", "carrots"]
> food.first
=> "chicken"
> food.last
=> "carrots"
> food.length
=> 7
> food.count
=> 7
> food.include?("chicken")
=> true
> food.include?("filet mignon")
=> false
> food.empty?
=> false
> food[0]
=> "chicken"
> food[0].eql?("chicken")
=> true
> food[0].eql?("beef")
=> false
> food.sort
=> ["beef", "carrots", "chicken", "fish", "rice", "shrimp", "steak"]
In the brackets right after eql?, we put the string in double quotes because we are dealing with a string. Also, sort arranges alphabetically on strings and from lowest to highest for numbers.
We can store anything in each element, not just strings. We can even mix; some elements can be strings, others can be numbers.
Say we wanted an array of numbers. We would do something like this:
numbers = [1, 2, 3, 4, 5, 6] => [1, 2, 3, 4, 5, 6]
Remember what we said earlier about always starting the index at 0. You can see here why that is so important. In order to reference the number 1 in this array, the array reference has to be [0] because that is the first element in the array.
> numbers[0] => 1 > numbers[1] => 2 > numbers[6] => nil > numbers.first => 1 > numbers.last => 6 > numbers.count => 6 > numbers.length => 6 > numbers.include?(3) => true > numbers.include?(10) => false > numbers.empty? => false > numbers[1] => 2 > numbers[1].eql?(1) => false > numbers[1].eql?(2) => true
Because we are evaluating numbers, the objects in the brackets should not be wrapped in double quotes. In fact, if we did use double quotes, Ruby wouldn’t find the items because it would be looking for a string and not a number. Be careful with those quotes!
> numbers.include?("3")
=> false
> numbers[1].eql?("2")
=> false
To see what other Ruby methods are included in the array class, check the documentation on “Array.”
Everything we’ve just discussed covers one-dimensional arrays (i.e. arrays with just one column). These are best used to store lists of items.
As you can imagine, there are multi-dimensional arrays. We’ll just touch on a 2-D array. Once you understand how to use them, you can then extrapolate to 3-D and beyond (if you ever want to go there).
A 2-D array looks like this:
We are storing two things: the name of the dish, along with a price related to that item.
As the diagram suggests, in order to access each element, you would use both keys.
This is how we would declare this array:
> food2 = [["chicken", 10], ["rice", 5], ["steak", 20], ["fish", 15], ["shrimp", 18], ["beef", 9]] => [["chicken", 10], ["rice", 5], ["steak", 20], ["fish", 15], ["shrimp", 18], ["beef", 9]]
A few key differences should jump out at you. Essentially, food2 is an array of arrays (meaning that it is an array whose elements are themselves arrays). Huh? Well, look at each element.
> food2[0] => ["chicken", 10] > food2[1] => ["rice", 5] > food2[2] => ["steak", 20] > food2[3] => ["fish", 15]
When you access each “single” element, you notice that each has an array inside of it; ["chicken", 10] is an array that has a string (chicken) in the first element and a number (10) in the second element.
So, to access each individual element, we would do something like this:
> food2[0] => ["chicken", 10] > food2[0][0] => "chicken" > food2[0][1] => 10
First, food2[0][0] is saying, “Show me the first element of the first element of the array food2.” And food2[0][1] is saying, “Show me the second element of the first element of the array food2.”
You can also use the same methods of the Ruby class array on subarrays.
> food2 => [["chicken", 10], ["rice", 5], ["steak", 20], ["fish", 15], ["shrimp", 18], ["beef", 9]] > food2.count => 6 > food2[0] => ["chicken", 10] > food2[0].count => 2 > food2.last => ["beef", 9] > food2.first => ["chicken", 10]
Keep in mind one important distinction for multi-dimensional arrays: Ruby will check whatever you call the method on.
For instance, if you wanted to check whether chicken is in the food2 array, you could not do this:
> food2.include?("chicken")
=> false
The reason is that food2 is just an array of arrays. So, you would have to do something like this:
> food2
=> [["chicken", 10], ["rice", 5], ["steak", 20], ["fish", 15], ["shrimp", 18], ["beef", 9]]
> food2[0].include?("chicken")
=> true
We had to specify the particular element ([0]) that we wanted to check for the string chicken.
In this case, we knew that the string chicken was stored in food2[0] because we put it there. How would we find it if we didn’t know? We’d have to use an iterator.
An iterator is a mechanism in Ruby that enables you to cycle through data structures that store multiple elements (such as an array) and examine each element. One of the most commonly used methods is named each. Each is a method in the array class that comes with Ruby.
Let’s start simple. Suppose we wanted to print a list of all of our food items stored in the food array. How would we do this?
> food => ["chicken", "rice", "steak", "fish", "beef"] food.each do |x| puts x end chicken rice steak fish beef
A few things to be aware of here:
each on a collection of data.each, you have to pass a block to it. A block is just a contained bit of code. Basically, you are saying to apply the code contained within the block to each element that you look at.There are two ways to use a block. The first is similar to the example above, where you just do this:
do |variable| #some code end
Note that you have to use a block with an iterator. You can define a block outside of an iterator, but in order to execute the block, you have to use it in conjunction with an iterator. That’s why we called do |x| after food.each earlier.
You can use one or more variables in your block. Those variables are local to the block alone, so they will be destroyed once you leave. Thus, if you had two blocks, you could use the variable x in both, and one wouldn’t affect the other.
In the example above about food, we have said, for each element in the array food, print it to the screen.
Another way to use a block is on one line, like this:
food.each { |x| puts x }
In this case, the opening curly brace ({) replaces the do, and the closing curly brace replaces the end. If your operation is just one line, then this way is convenient, although I have found that rereading such code in future is sometimes harder; so, I usually just use do and end, but that’s a personal preference. Do whatever makes you most comfortable.
The reason that blocks use variables is because the elements of the collection are actually not modified — unless you specifically chose to do so. Basically, what happens is that for every single iteration through the array, a copy of the new element is stored in x, and then x is used in the block.
Going through the food array, the local block variable x would look something like the following.
First iteration:
food[0] = 'chicken' x = food[0] x = 'chicken'
Second iteration:
food[1] = 'rice' x = food[1] x = 'rice'
Third iteration:
food[2] = 'steak' x = food[2] x = 'steak'
Using numbers would more clearly illustrate that the values aren’t changed in the original array:
> numbers = [1, 2, 3, 4, 5] => [1, 2, 3, 4, 5] > numbers.each do |x| … x = x + 2 … puts x … end 3 4 5 6 7 > numbers => [1, 2, 3, 4, 5]
Here we’ve printed out the numbers 3, 4, 5, 6, 7 (i.e. 1+2, 2+2, 3+2, etc.); but at the end, the numbers array is the same.
A hash is another collection type. It is a collection of “key-value” pairs. A key-value pair is a combination of the name of a container (i.e. the key) and the contents of the container (i.e. the value).
a => "Marc"
In the key-value pair above, the key is a, and the value is Marc.
A hash, then, is basically a list of these key-value pairs, separated by commas. A hash looks like this:
a =>"Marc", b => "Cheyenne", c => "Alexander", d=> "Mia"
Hashes and arrays have some key differences, though, and some things to note:
a is “first” or that it “comes before” b in the example above, because Ruby does not look at the order of keys in hashes.Marc, Cheyenne, etc. But don’t confuse this with the way in which array keys are ordered.There are multiple ways to initialize (or initially create) a hash, but the most popular ways look something like the following.
To create an empty hash (i.e. a hash with no values):
> day = Hash.new
=> {}
To create a hash with particular values:
> names = Hash["a" => "Marc", "b" => "Cheyenne", "c" => "Alexander", "d" => "Mia"]
=> {"a"=>"Marc", "b"=>"Cheyenne", "c"=>"Alexander", "d"=>"Mia"}
> names2 = {"a" => "Marc", "b" => "Cheyenne"}
=> {"a" => "Marc", "b" =>"Cheyenne"}
You will notice that to create the hash, you don’t have to use the keyword Hash or square brackets ([]). You can use them if you like, or you can just use = { }.
For the keys and values, you also don’t need to put the keys in quotes. You need to do that only if you want to use strings as the key. Ruby also requires a => (pronounced “rocket”) to assign the value on the right side of the rocket to the key on the left side.
If you tried to do names2 without the quotes around the keys, you would likely get an error like this:
> names2 = { a => "Marc", b => "Cheyenne"}
=> #<NameError: undefined local variable or method `a' for main:Object>
To access values within the hash, you have to specify the name of the hash, along with the key for the value you are trying to access.
> names
=> {"a"=>"Marc", "b"=>"Cheyenne", "c"=>"Alexander", "d"=>"Mia"}
> names["a"]
=> "Marc"
> names["c"]
=> "Alexander"
> names[a]
=> #<NameError: undefined local variable or method `a' for main:Object>
Because we didn’t use quotes for names[a], the Ruby interpreter thinks that a is a local variable or a method and so can’t find a value for it, thus throwing an error.
If you tried to access a seemingly legitimate value via a legitimate key that has not been assigned a value, then Ruby would usually return nil.
> day["a"] => nil > day[9] => nil #For you Day9 fans, don't worry… I am a fan too :)
Suppose you wanted to create a hash in which every value has a “default” value. You could do something like this:
> year = Hash.new("2012")
=> {}
> year[0]
=> "2012"
> year[12]
=> "2012"
All we’ve done was call the method new on the Ruby class Hash and pass the default value of 2012 into that method. So, when trying to access a value that doesn’t exist, instead of returning nil, Ruby would return the default value (2012).
You can use a number of methods with hashes:
> names.keys => ["a", "b", "c", "d", "e"] > names.values => ["Marc", "Cheyenne", "Alexander", "Mia", "Christopher"]
As you can guess, the keys just returns all of the keys in the hash, and the values returns all of the values.
> names.length
=> 5
> names.has_key?("a")
=> true
> names.has_key?("z")
=> false
> names.has_key("a")
=> #<NoMethodError: undefined method `has_key' for #<Hash:0x55c797d7>>
Note that the name of the has_key method is actually has_key?. If you left out the ?, it would throw an error like the one above.
All that has_key? is doing is checking the hash to see whether any key matches whatever is in the brackets. If it finds a match, then it returns true; if it doesn’t, it returns false.
> f_names = names
=> {"a"=>"Marc", "b"=>"Cheyenne", "c"=>"Alexander", "d"=>"Mia", "e"=>"Christopher"}
> l_names = {"g" => "Gayle", "h" => "Gayle", "j" => "Jackson", "m" => "Brown"}
=> {"g"=>"Gayle", "h"=>"Gayle", "j"=>"Jackson", "m"=>"Brown"}
> f_names.merge(l_names)
=> {"a"=>"Marc", "b"=>"Cheyenne", "c"=>"Alexander", "d"=>"Mia", "e"=>"Christopher", "g"=>"Gayle", "h"=>"Gayle","j"=>"Jackson", "m"=>"Brown"}
> f_names
=> {"a"=>"Marc", "b"=>"Cheyenne", "c"=>"Alexander", "d"=>"Mia", "e"=>"Christopher"}
> l_names
=> {"g"=>"Gayle", "h"=>"Gayle", "j"=>"Jackson", "m"=>"Brown"}
All we’ve done above was create a new hash, f_names, by assigning it the existing names hash. Then, we created another hash, l_names, that has a few last names. Then, we just merged the two hashes to create a master hash. However, because we just ran the merge method without assigning the result to any variable, it wasn’t stored. If you check the values of f_names and l_names after, you will see that they look exactly the same as before we ran merge.
If we wanted to store the value of the merge, we would have had to do something like this:
> master_hash = f_names.merge(l_names)
=> {"a"=>"Marc", "b"=>"Cheyenne", "c"=>"Alexander", "d"=>"Mia", "e"=>"Christopher", "g"=>"Gayle", "h"=>"Gayle", "j"=>"Jackson", "m"=>"Brown"}
Another approach is to do a “destructive” merge. This is an interesting feature of Ruby. For many (perhaps most) methods, if you add an exclamation point to the end of the method’s call, you actually replace the value of the method’s caller with the returned value. For example:
> f_names
=> {"a"=>"Marc", "b"=>"Cheyenne", "c"=>"Alexander", "d"=>"Mia", "e"=>"Christopher"}
> l_names
=> {"g"=>"Gayle", "h"=>"Gayle", "j"=>"Jackson", "m"=>"Brown"}
> f_names.merge!(l_names)
=> {"a"=>"Marc", "b"=>"Cheyenne", "c"=>"Alexander", "d"=>"Mia", "e"=>"Christopher", "g"=>"Gayle", "h"=>"Gayle", "j"=>"Jackson", "m"=>"Brown"}
> f_names
=> {"a"=>"Marc", "b"=>"Cheyenne", "c"=>"Alexander", "d"=>"Mia", "e"=>"Christopher", "g"=>"Gayle", "h"=>"Gayle", "j"=>"Jackson", "m"=>"Brown"}
As you can see, the f_names value after we ran the destructive merge method (merge!) is now the same value as the merged hash.
Another method that you can use with hashes is each. But it is slightly different. With arrays, you just have to pass in one variable to the block (which essentially represents the index of the array). With hashes, you have to pass in two variables: one that represents the key, and another that represents the value.
> f_names.each do |key, value|
.. puts "#{key} is #{value}"
.. end
=> "a is Marcb is Cheyennec is Alexanderd is Miae is Christopherg is Gayleh is Gaylej is Jacksonm is Brown"
This looks a little messy. Here is what’s happening:
key and value. So, after the first iteration, key would be a, and value would be Marc.puts, followed by a string. In other words, it will print everything in quotes to the screen.puts? That’s called “string interpolation.” It basically says, stick the value of this variable into my string at this exact position. Thus, after the first iteration, puts would do this:
a).is).is).Marc). (The entire string, after the first iteration, would be a is Marc.)puts command is done.end, so goes back to the beginning of the block to see whether any more elements are in this hash object.puts line (and we didn’t put a space after the first quote on the puts line), no space will be between the last character of the first iteration and the first character of the second iteration.puts looks like puts " #{key} is #{value}", then the resulting string might make more sense: a is Marc b is Cheyenne c is Alexander etc.I intended for the output to make sense, but when I saw the result, I realized that this has tripped me up many times in my career, so I figured to highlight it.
You can use a lot more methods on hashes, many of which you should be familiar with because they look like others we have covered here, such as value? (note the ? — I’m not asking a question here), and they look similar to the methods we went over in the arrays section, such as include?, empty?, eql?, size, etc.
The last element of Ruby that you should be familiar with is an object type called a symbol.
A symbol is an object type that resembles a string, but is not quite one. The major difference between a symbol and a string is that a symbol always begins with a colon (like :name). (For more information, see the “Symbol” article in the Ruby documentation and “The Ruby_Newbie Guide to Symbols” on Troubleshooters.com)
Symbols work nicely with hashes because you can use them as the keys instead of strings.
> f_names
=> {:a =>"Marc", :b =>"Cheyenne", :c =>"Alexander", :d =>"Mia", :e =>"Christopher"}
> f_names[:a]
=> "Marc"
The good thing about this is that you no longer have to worry about all of those quotes for both the keys and the values… but you can still remember the words for the keys.
> pets = {:dog => "Cookie", :cat => "Snowy", :fish => "Goldie"}
=> {:dog=>"Cookie", :cat=>"Snowy", :fish=>"Goldie"}
> pets[:dog]
=> "Cookie"
> pets[:fish]
=> "Goldie"
Symbols make dealing with hashes much simpler than using strings as keys. You can, of course, use hashes for anything else in the Ruby language; their main function is to store values and make retrieval easier on the interpreter (since handling strings has many rules).
I hope you have learned a lot here. Remember that this guide to Ruby is not comprehensive, but simply an introduction tailored to those with little or no programming experience. It’s not written in the typical programming tutorial style because I’ve always found that to be a bit difficult. I need to understand the whys behind the whats, so I’ve taken that approach here. I also don’t profess to be a Ruby ninja; I just wanted to learn how to build Web products myself, so I taught myself Ruby and Rails.
You now have the foundation to play with Try Ruby some more or to install Ruby on your system and get started (Google it).
Good luck, and remember that true learning often happens when you are struggling with a problem. When you spend one week stuck on a “very simple” problem and you eventually figure it out, you are guaranteed not to make that mistake again. And when you get stuck, don’t panic. Just take a break; maybe Google it and see what solutions others have had. But don’t just copy and paste code. Figure out why it does what it does and how it can help you. That’s how you learn.
If I was unclear with anything, please let me know in the comments.
There are fabulous books on Ruby to help get you started. Here are some of my favorites.
(al) (km)
© Marc Gayle for Smashing Magazine, 2012.
Submitted by: cool
Posted at: 2012-05-24 19:03:55
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Submitted by: hellokittybaby6
Posted at: 2012-05-24 16:07:13
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