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Booleans

The boolean type is used to represent the truth value of an expression. For example, the expression 1 <= 2 is true , while the expression 0 == 1 is false. Expressions that evaluate to a boolean type are called boolean expressions.

Literals​

true​

true value is always true.

Another way you may come across is True. But you should use the lowercase version for consistency (all Jinja identifiers are lowercase).

See also: Jinja Docs.

false​

false value is always false.

Another way you may come across is False. But you should use the lowercase version for consistency (all Jinja identifiers are lowercase).

See also: Jinja Docs.

Operators​

== != > >= < <=​

Use this operators to build simple boolean expressions.

  • == - Compares two objects for equality.
  • != - Compares two objects for inequality.
  • > - true if the left hand side is greater than the right hand side.
  • >= - true if the left hand side is greater or equal to the right hand side.
  • < - true if the left hand side is lower than the right hand side.
  • <= - true if the left hand side is lower or equal to the right hand side.

See also: Jinja Docs, Python Docs.

and or not​

  • The expression x and y yields false if x is false, otherwise the value of y is returned.
  • The expression x or y yields true if x is true, otherwise the value of y is returned.
  • The expression not x yields true if x is false, false otherwise.

Note that and or does NOT always return bool type, but rather return the last evaluated argument. For example,

{% set x = "hello world" %} {# true #}
{% set y = "" %}  {# false #}

"{{ x and y }}"
-> ""

{{ x or y }}
-> hello world

{{ not x }}
-> false

The same is true for other types such as numbers, lists, etc.

When using it as a conditional expression in an {% if ... %} statement, the result is tested as a boolean value, so there is no need to worry about it, but be careful when using the return value in subsequent operations.

See also: Jinja Docs, Python Docs.

Tests​

x is boolean​

Return true if the object is a boolean value.

{{ (0 == 1) is boolean }}
-> true

See also: Jinja Docs.

x is true​

Return true if the object is true.

{{ (1 == 1) is true }}
-> true

See also: Jinja Docs.

x is false​

Return true if the object is false.

{{ (0 == 1) is false }}
-> true

See also: Jinja Docs.

Tests: Comparisons​

x is eq y​

Same as x == y.

Aliases: ==, equalto.

{{ [1, 2, 3, 2]|select('eq', 2)|list }}
-> [2, 2]

See also: Jinja Docs, list|select.

x is ge y​

Same as x >= y.

Aliases: >=.

{{ [1, 2, 3, 2]|select('ge', 2)|list }}
-> [2, 3, 2]

See also: Jinja Docs, list|select.

x is gt y​

Same as x > y.

Aliases: >, greaterthan.

{{ [1, 2, 3, 2]|select('gt', 2)|list }}
-> [3]

See also: Jinja Docs, list|select.

x is le y​

Same as x <= y.

Aliases: <=.

{{ [1, 2, 3, 2]|select('le', 2)|list }}
-> [1, 2, 2]

See also: Jinja Docs, list|select.

x is lt y​

Same as x < y.

Aliases: <, lessthan.

{{ [1, 2, 3, 2]|select('lt', 2)|list }}
-> [1]

See also: Jinja Docs, list|select.

x is ne y​

Same as x != y.

Aliases: !=.

{{ [1, 2, 3, 2]|select('ne', 2)|list }}
-> [1, 3]

See also: Jinja Docs, list|select.