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Operators
An operator is a statement that evaluates some code, and makes a decision about what to do next. Operators can be used for comparing two values, inspecting a single value, or evaluating whether or not some code returns
true.For further discussion on how Liquid treats values, see their documentation: Truthiness and falsiness in Liquid.
If
b = 6, the table below illustrates the comparison operators and the way they interact with b:Operator | Description | Example | Result |
== | equal to | b == 6 | true |
!= | not equal | b != 6 | false |
> | greater than | b > 5 | true |
< | less than | b < 6 | false |
>= | greater than or equal to | b >= 6 | true |
<= | less than or equal to | b <= 6 | true |
{% assign order_qualifies = false %}
{% if order.cancelled_at == blank and cancel_risk %}
{% assign order_qualifies = true %}
{% endif %}
{% if has_product != true %}
{% log "Order has no products; skipping" %}
{% assign send_email = false %}
{% endif %}
Liquid supports equality/inequality testing a value against
blank or empty. In this way, Liquid allows the author to ask, "is this value blank?", or "is this value empty?"An object is blank if it's false, empty, or a whitespace string. For example,nil, '', ' ', [], {}, andfalseare all blank.
{% assign empty_string = "" %}
{% assign whitespace_string = " " %}
{% assign non_blank_string = " !! " %}
{% assign non_empty_array = "1,2,3" | split: "," %}
{% assign empty_hash = hash %}
{% comment %}
The following `if` statements all pass.
{% endcomment %}
{% if empty_string == blank %}
{% if whitespace_string == blank %}
{% if non_blank_string != blank %}
{% if non_empty_array != blank %}
{% if empty_hash == blank %}
An array, hash, or string can be tested for emptiness. An array is empty if it has no elements; a hash is empty if it has no key-value pairs; a string is empty if its length is zero.
A string that only contains whitespace is not empty, but it is blank!
{% assign empty_string = "" %}
{% assign whitespace_string = " " %}
{% assign non_blank_string = " !! " %}
{% assign non_empty_array = "1,2,3" | split: "," %}
{% assign empty_hash = hash %}
{% comment %}
The following `if` statements all pass.
{% endcomment %}
{% if empty_string == empty %}
{% if whitespace_string != empty %}
{% if non_blank_string != empty %}
{% if non_empty_array != empty %}
{% if empty_hash == empty %}
The
contains operator is used to check for the existence of a substring in a string, or for a specific element in an array.{% if email_domain contains "@" %}
{% error "Do not include '@' symbols in email domains. Thanks!" %}
{% endif %}
{% assign product_tags = "foo, bar, baz" | split: ", " %}
{% assign product_is_tagged_bar = false %}
{% if product_tags contains "bar" %}
{% assign product_is_tagged_bar = true %}
{% endif %}
Liquid has two logical operators:
and and or.If
b = 3 and c = 6, the table below illustrates the logical operators in Liquid, and the way they interact with b and b:Operator | Example | Result |
and | b < 2 and c < 6 | false |
or | b < 2 or c < 6 | true |
{% if order.shipping_address != blank and order.billing_address != blank %}
{% comment %} do something {% endcomment %}
{% endif %}
{% if tag == blank or customer.tags contains tag %}
{% comment %} do something {% endcomment %}
{% endif %}
Last modified 2yr ago