liquid/basics/types.md

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Types

Liquid objects can have one of six types:

• string
• number
• boolean
• nil
• array
• EmptyDrop

Liquid variables can be initialized by using the assign or capture tags.

String

Strings are declared by wrapping a variable's value in single or double quotes.

{% highlight liquid %} {% raw %} {% assign my_string = "Hello World!" %} {% endraw %} {% endhighlight %}

Number

Numbers include floats and integers.

{% highlight liquid %} {% raw %} {% assign my_int = 25 %} {% assign my_float = 39.756 %} {% endraw %} {% endhighlight %}

Boolean

Booleans are either true or false. No quotations are necessary when declaring a boolean.

{% highlight liquid %} {% raw %} {% assign foo = true %} {% assign bar = false %} {% endraw %} {% endhighlight %}

Nil

Nil is a special empty value that is returned when Liquid code has no results. It is not a string with the characters "nil".

Nil is treated as false in the conditions of if blocks and other Liquid tags that check the truthfulness of a statement.

In the following example, if the user does not exist (that is, user returns nil), Liquid will not print the greeting:

{% highlight liquid %} {% raw %} {% if user %} Hello {{ user.name }}! {% endif %} {% endraw %} {% endhighlight %}

Tags or outputs that return nil will not print anything to the page.

{% highlight liquid %}{% raw %} The current user is {{ user.name }} {% endraw %}{% endhighlight %}

{% highlight text %}{% raw %} The current user is {% endraw %}{% endhighlight %}

Array

Arrays hold lists of variables of any type.

Accessing items in arrays

To access all of the items in an array, you can loop through each item in the array using a for or tablerow tag.

{% highlight liquid %}{% raw %} {% for user in site.users %} {{ user }} {% endfor %} {% endraw %}{% endhighlight %}

{% highlight text %}{% raw %} Tobi Lina Tetsuro Adam {% endraw %}{% endhighlight %}

Accessing specific items in arrays

You can use square bracket [ ] notation to access a specific item in an array. Array indexing starts at zero.

{% highlight liquid %}{% raw %} {{ site.users[0] }} {{ site.users[1] }} {{ site.users[3] }} {% endraw %}{% endhighlight %}

{% highlight text %}{% raw %} Tobi Lina Adam {% endraw %}{% endhighlight %}

Initializing arrays

You cannot initialize arrays using pure Liquid.

You can, however, use the split filter to break a single string into an array of substrings.

EmptyDrop

An EmptyDrop object is returned if you try to access a deleted object (such as a page or post) by its handle. In the example below, page_1, page_2 and page_3 are all EmptyDrop objects.

{% highlight liquid %}{% raw %} {% assign variable = "hello" %} {% assign page_1 = pages[variable] %} {% assign page_2 = pages["does-not-exist"] %} {% assign page_3 = pages.this-handle-does-not-exist %} {% endraw %}{% endhighlight %}

EmptyDrop objects only have one attribute, empty?, which is always true.

Collections and pages that do exist do not have an empty? attribute. Their empty? is “falsy”, which means that calling it inside an if statement will return false. When using an unless statement on existing collections and pages, empty? will return true.

Checking for emptiness

Using the empty? attribute, you can check to see if an object exists or not before you access any of its attributes.

{% highlight liquid %}{% raw %} {% unless pages.about.empty? %}

{{ pages.frontpage.title }}

{{ pages.frontpage.content }}

{% endunless %} {% endraw %}{% endhighlight %}

If you don't check for emptiness first, Liquid may print empty HTML elements to the page:

{% highlight html %}{% raw %}

{% endraw %}{% endhighlight %}