zip($lists...) Combines several lists into a single multidimensional list. The nth value of the resulting list is a space separated list of the source lists’ nth values. The length of the resulting list is the length of the shortest list. Examples: zip(1px 1px 3px, solid dashed solid, red green blue) => 1px solid red, 1px dashed green, 3px solid blue Parameters: $lists ([Base]) Returns: (List)

variable_exists($name) Check whether a variable with the given name exists in the current scope or in the global scope. Examples: $a-false-value: false; variable-exists(a-false-value) => true variable-exists(nonexistent) => false Parameters: $name (String) — The name of the variable to check. The name should not include the $. Returns: (Bool) — Whether the variable is defined in the current scope.

unquote($string) Removes quotes from a string. If the string is already unquoted, this will return it unmodified. Examples: unquote("foo") => foo unquote(foo) => foo Parameters: $string (String) Returns: (String) Raises: (ArgumentError) — if $string isn’t a string

unitless($number) Returns whether a number has units. Examples: unitless(100) => true unitless(100px) => false Parameters: $number (Number) Returns: (Bool) Raises: (ArgumentError) — if $number isn’t a number

unit($number) Returns the unit(s) associated with a number. Complex units are sorted in alphabetical order by numerator and denominator. Examples: unit(100) => "" unit(100px) => "px" unit(3em) => "em" unit(10px * 5em) => "em*px" unit(10px * 5em / 30cm / 1rem) => "em*px/cm*rem" Parameters: $number (Number) Returns: (String) — The unit(s) of the number, as a quoted string Raises: (ArgumentError) — if $number isn’t a number

unique_id Returns a unique CSS identifier. The identifier is returned as an unquoted string. The identifier returned is only guaranteed to be unique within the scope of a single Sass run. Returns: (String)

type_of($value) Returns the type of a value. Examples: type-of(100px) => number type-of(asdf) => string type-of("asdf") => string type-of(true) => bool type-of(#fff) => color type-of(blue) => color Parameters: $value (Base) — The value to inspect Returns: (String) — The unquoted string name of the value’s type

transparentize($color, $amount) Also known as: fade_out Makes a color more transparent. Takes a color and a number between 0 and 1, and returns a color with the opacity decreased by that amount. Examples: transparentize(rgba(0, 0, 0, 0.5), 0.1) => rgba(0, 0, 0, 0.4) transparentize(rgba(0, 0, 0, 0.8), 0.2) => rgba(0, 0, 0, 0.6) Parameters: $color (Color) $amount (Number) — The amount to decrease the opacity by, between 0 and 1 Returns: (Color) Raises: (ArgumentError) —

to_upper_case($string) Converts a string to upper case. Examples: to-upper-case(abcd) => ABCD Parameters: $string (String) Returns: (String) Raises: (ArgumentError) — if $string isn’t a string

to_lower_case($string) Convert a string to lower case, Examples: to-lower-case(ABCD) => abcd Parameters: $string (String) Returns: (String) Raises: (ArgumentError) — if $string isn’t a string