sass-site/source/documentation/modules/list.liquid
2023-06-02 18:18:43 -04:00

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---
title: sass:list
---
{% render 'doc_snippets/built-in-module-status' %}
{% funFact %}
In Sass, every [map][] counts as a list that contains a two-element list for
each key/value pair. For example, `(1: 2, 3: 4)` counts as `(1 2, 3 4)`. So
all these functions work for maps as well!
[map]: /documentation/values/maps
Individual values also count as lists. All these functions treat `1px` as a
list that contains the value `1px`.
{% endfunFact %}
{% function 'list.append($list, $val, $separator: auto)', 'append($list, $val, $separator: auto)', 'returns:list' %}
{% markdown %}
Returns a copy of `$list` with `$val` added to the end.
If `$separator` is `comma`, `space`, or `slash`, the returned list is
comma-separated, space-separated, or slash-separated, respectively. If it's
`auto` (the default), the returned list will use the same separator as
`$list` (or `space` if `$list` doesn't have a separator). Other values
aren't allowed.
[separator]: /documentation/values/lists
Note that unlike [`list.join()`](#join), if `$val` is a list it's nested
within the returned list rather than having all its elements added to the
returned list.
{% endmarkdown %}
{% codeExample 'list-append', false %}
@debug list.append(10px 20px, 30px); // 10px 20px 30px
@debug list.append((blue, red), green); // blue, red, green
@debug list.append(10px 20px, 30px 40px); // 10px 20px (30px 40px)
@debug list.append(10px, 20px, $separator: comma); // 10px, 20px
@debug list.append((blue, red), green, $separator: space); // blue red green
===
@debug list.append(10px 20px, 30px) // 10px 20px 30px
@debug list.append((blue, red), green) // blue, red, green
@debug list.append(10px 20px, 30px 40px) // 10px 20px (30px 40px)
@debug list.append(10px, 20px, $separator: comma) // 10px, 20px
@debug list.append((blue, red), green, $separator: space) // blue red green
{% endcodeExample %}
{% endfunction %}
{% function 'list.index($list, $value)', 'index($list, $value)', 'returns:number | null' %}
{% markdown %}
Returns the [index][] of `$value` in `$list`.
[index]: /documentation/values/lists#indexes
If `$value` doesn't appear in `$list`, this returns [`null`][]. If `$value`
appears multiple times in `$list`, this returns the index of its first
appearance.
[`null`]: /documentation/values/null
{% endmarkdown %}
{% render 'code_snippets/example-list-index' %}
{% endfunction %}
{% function 'list.is-bracketed($list)', 'is-bracketed($list)', 'returns:boolean' %}
{% markdown %}
Returns whether `$list` has square brackets.
{% endmarkdown %}
{% codeExample 'list-is-bracketed', false %}
@debug list.is-bracketed(1px 2px 3px); // false
@debug list.is-bracketed([1px, 2px, 3px]); // true
===
@debug list.is-bracketed(1px 2px 3px) // false
@debug list.is-bracketed([1px, 2px, 3px]) // true
{% endcodeExample %}
{% endfunction %}
{% function 'list.join($list1, $list2, $separator: auto, $bracketed: auto)', 'join($list1, $list2, $separator: auto, $bracketed: auto)', 'returns:list' %}
{% markdown %}
Returns a new list containing the elements of `$list1` followed by the
elements of `$list2`.
{% endmarkdown %}
{% headsUp %}
Because individual values count as single-element lists, it's possible to
use `list.join()` to add a value to the end of a list. However, *this is not
recommended*, since if that value is a list it will be concatenated, which
is probably not what you're expecting.
Use [`list.append()`](#append) instead to add a single value to a list. Only
use `list.join()` to combine two lists together into one.
{% endheadsUp %}
{% markdown %}
If `$separator` is `comma`, `space`, or `slash`, the returned list is
comma-separated, space-separated, or slash-separated, respectively. If it's
`auto` (the default), the returned list will use the same separator as
`$list1` if it has a separator, or else `$list2` if it has a separator, or
else `space`. Other values aren't allowed.
If `$bracketed` is `auto` (the default), the returned list will be bracketed
if `$list1` is. Otherwise, the returned list will have square brackets if
`$bracketed` is [truthy] and no brackets if `$bracketed` is falsey.
[truthy]: /documentation/values/booleans#truthiness-and-falsiness
{% endmarkdown %}
{% codeExample 'list-join', false %}
@debug list.join(10px 20px, 30px 40px); // 10px 20px 30px 40px
@debug list.join((blue, red), (#abc, #def)); // blue, red, #abc, #def
@debug list.join(10px, 20px); // 10px 20px
@debug list.join(10px, 20px, $separator: comma); // 10px, 20px
@debug list.join((blue, red), (#abc, #def), $separator: space); // blue red #abc #def
@debug list.join([10px], 20px); // [10px 20px]
@debug list.join(10px, 20px, $bracketed: true); // [10px 20px]
===
@debug list.join(10px 20px, 30px 40px) // 10px 20px 30px 40px
@debug list.join((blue, red), (#abc, #def)) // blue, red, #abc, #def
@debug list.join(10px, 20px) // 10px 20px
@debug list.join(10px, 20px, comma) // 10px, 20px
@debug list.join((blue, red), (#abc, #def), space) // blue red #abc #def
@debug list.join([10px], 20px) // [10px 20px]
@debug list.join(10px, 20px, $bracketed: true) // [10px 20px]
{% endcodeExample %}
{% endfunction %}
{% function 'list.length($list)', 'length($list)', 'returns:number' %}
{% markdown %}
Returns the length of `$list`.
This can also return the number of pairs in a map.
{% endmarkdown %}
{% codeExample 'list-length', false %}
@debug list.length(10px); // 1
@debug list.length(10px 20px 30px); // 3
@debug list.length((width: 10px, height: 20px)); // 2
===
@debug list.length(10px) // 1
@debug list.length(10px 20px 30px) // 3
@debug list.length((width: 10px, height: 20px)) // 2
{% endcodeExample %}
{% endfunction %}
{% function 'list.separator($list)', 'list-separator($list)', 'returns:unquoted string' %}
{% markdown %}
Returns the name of the separator used by `$list`, either `space`, `comma`,
or `slash`.
If `$list` doesn't have a separator, returns `space`.
{% endmarkdown %}
{% codeExample 'list-separator', false %}
@debug list.separator(1px 2px 3px); // space
@debug list.separator(1px, 2px, 3px); // comma
@debug list.separator('Helvetica'); // space
@debug list.separator(()); // space
===
@debug list.separator(1px 2px 3px) // space
@debug list.separator(1px, 2px, 3px) // comma
@debug list.separator('Helvetica') // space
@debug list.separator(()) // space
{% endcodeExample %}
{% endfunction %}
{% function 'list.nth($list, $n)', 'nth($list, $n)' %}
{% markdown %}
Returns the element of `$list` at [index][] `$n`.
[index]: /documentation/values/lists#indexes
If `$n` is negative, it counts from the end of `$list`. Throws an error if
there is no element at index `$n`.
{% endmarkdown %}
{% render 'code_snippets/example-list-nth' %}
{% endfunction %}
{% function 'list.set-nth($list, $n, $value)', 'set-nth($list, $n, $value)', 'returns:list' %}
{% markdown %}
Returns a copy of `$list` with the element at [index][] `$n` replaced with
`$value`.
[index]: /documentation/values/lists#indexes
If `$n` is negative, it counts from the end of `$list`. Throws an error if
there is no existing element at index `$n`.
{% endmarkdown %}
{% codeExample 'list-set-nth', false %}
@debug list.set-nth(10px 20px 30px, 1, 2em); // 2em 20px 30px
@debug list.set-nth(10px 20px 30px, -1, 8em); // 10px, 20px, 8em
@debug list.set-nth((Helvetica, Arial, sans-serif), 3, Roboto); // Helvetica, Arial, Roboto
===
@debug list.set-nth(10px 20px 30px, 1, 2em); // 2em 20px 30px
@debug list.set-nth(10px 20px 30px, -1, 8em); // 10px, 20px, 8em
@debug list.set-nth((Helvetica, Arial, sans-serif), 3, Roboto); // Helvetica, Arial, Roboto
{% endcodeExample %}
{% endfunction %}
{% function 'list.slash($elements...)', 'returns:list' %}
{% markdown %}
Returns a slash-separated list that contains `$elements`.
{% endmarkdown %}
{% headsUp %}
This function is a temporary solution for creating slash-separated lists.
Eventually, they'll be written literally with slashes, as in
`1px / 2px / solid`, but for the time being [slashes are used for division]
so Sass can't use them for new syntax until the old syntax is removed.
[slashes are used for division]: /documentation/breaking-changes/slash-div
{% endheadsUp %}
{% codeExample 'list-slash', false %}
@debug list.slash(1px, 50px, 100px); // 1px / 50px / 100px
===
@debug list.slash(1px, 50px, 100px) // 1px / 50px / 100px
{% endcodeExample %}
{% endfunction %}
{% function 'list.zip($lists...)', 'zip($lists...)', 'returns:list' %}
{% markdown %}
Combines every list in `$lists` into a single list of sub-lists.
Each element in the returned list contains all the elements at that position
in `$lists`. The returned list is as long as the shortest list in `$lists`.
The returned list is always comma-separated and the sub-lists are always
space-separated.
{% endmarkdown %}
{% codeExample 'list-zip', false %}
@debug list.zip(10px 50px 100px, short mid long); // 10px short, 50px mid, 100px long
@debug list.zip(10px 50px 100px, short mid); // 10px short, 50px mid
===
@debug list.zip(10px 50px 100px, short mid long) // 10px short, 50px mid, 100px long
@debug list.zip(10px 50px 100px, short mid) // 10px short, 50px mid
{% endcodeExample %}
{% endfunction %}