--- title: sass:list --- <%= partial '../snippets/built-in-module-status' %> <% fun_fact do %> 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]: ../values/maps Individual values also count as lists. All these functions treat `1px` as a list that contains the value `1px`. <% end %> <% function 'list.append($list, $val, $separator: auto)', 'append($list, $val, $separator: auto)', returns: 'list' do %> Returns a copy of `$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]: ../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. <% example(autogen_css: false) do %> @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, $separator: space) // blue red green <% end %> <% end %> <% function 'list.index($list, $value)', 'index($list, $value)', returns: 'number | null' do %> Returns the [index][] of `$value` in `$list`. [index]: ../values/lists#indexes If `$value` doesn't appear in `$list`, this returns [`null`][]. If `$value` appears multiple times in `$list`, this returns the index of its first appearance. [`null`]: ../values/null <%= partial 'code-snippets/example-list-index' %> <% end %> <% function 'list.is-bracketed($list)', 'is-bracketed($list)', returns: 'boolean' do %> Returns whether `$list` has square brackets. <% example(autogen_css: false) do %> @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 <% end %> <% end %> <% function 'list.join($list1, $list2, $separator: auto, $bracketed: auto)', 'join($list1, $list2, $separator: auto, $bracketed: auto)', returns: 'list' do %> Returns a new list containing the elements of `$list1` followed by the elements of `$list2`. <% heads_up do %> Because individual values count as single-element lists, it's possible to use `list.join()` to add a value to the end of a list. However, *this is not recommended*, since if that value is a list it will be concatenated, which is probably not what you're expecting. Use [`list.append()`](#append) instead to add a single value to a list. Only use `list.join()` to combine two lists together into one. <% end %> If `$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 `$list1` if it has a separator, or else `$list2` if it has a separator, or else `space`. Other values aren't allowed. If `$bracketed` is `true`, the returned list has square brackets. If it's `false`, the returned list has no brackets. If it's `auto` (the default), the returned list will be bracketed if `$list1` is. Other values aren't allowed. <% example(autogen_css: false) do %> @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, $bracketed: true) // [10px 20px] <% end %> <% end %> <% function 'list.length($list)', 'length($list)', returns: 'number' do %> Returns the length of `$list`. This can also return the number of pairs in a map. <% example(autogen_css: false) do %> @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 <% end %> <% end %> <% function 'list.separator($list)', 'list-separator($list)', returns: 'unquoted string' do %> Returns the name of the separator used by `$list`, either `space`, `comma`, or `slash`. If `$list` doesn't have a separator, returns `space`. <% example(autogen_css: false) do %> @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 <% end %> <% end %> <% function 'list.nth($list, $n)', 'nth($list, $n)' do %> Returns the element of `$list` at [index][] `$n`. [index]: ../values/lists#indexes If `$n` is negative, it counts from the end of `$list`. Throws an error if there is no element at index `$n`. <%= partial 'code-snippets/example-list-nth' %> <% end %> <% function 'list.set-nth($list, $n, $value)', 'set-nth($list, $n, $value)', returns: 'list' do %> Returns a copy of `$list` with the element at [index][] `$n` replaced with `$value`. [index]: ../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 `$n`. <% example(autogen_css: false) do %> @debug list.set-nth(10px 20px 30px, 1, 2em); // 2em 20px 30px @debug list.set-nth(10px 20px 30px, -1, 8em); // 10px, 20px, 8em @debug list.set-nth((Helvetica, Arial, sans-serif), 3, Roboto); // Helvetica, Arial, Roboto === @debug list.set-nth(10px 20px 30px, 1, 2em); // 2em 20px 30px @debug list.set-nth(10px 20px 30px, -1, 8em); // 10px, 20px, 8em @debug list.set-nth((Helvetica, Arial, sans-serif), 3, Roboto); // Helvetica, Arial, Roboto <% end %> <% end %> <% function 'list.slash($elements...)', returns: 'list' do %> Returns a slash-separated list that contains `$elements`. <% heads_up do %> This function is a temporary solution for creating slash-separated lists. Eventually, they'll be written literally with slashes, as in `1px / 2px / solid`, but for the time being [slashes are used for division] so Sass can't use them for new syntax until the old syntax is removed. [slashes are used for division]: ../breaking-changes/slash-div <% end %> <% example(autogen_css: false) do %> @debug list.slash(1px, 50px, 100px); // 10px / 50px / 100px === @debug list.slash(1px, 50px, 100px) // 10px / 50px / 100px <% end %> <% end %> <% function 'list.zip($lists...)', 'zip($lists...)', returns: 'list' do %> Combines every list in `$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. <% example(autogen_css: false) do %> @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 <% end %> <% end %>