sass-site/source/documentation/operators/equality.html.md.erb
2018-10-23 13:42:40 -07:00

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---
title: Equality Operators
---
<% impl_status dart: true, libsass: false, ruby: '4.0.0 (unreleased)' do %>
LibSass and older versions of Ruby Sass consider numbers without units to be
equal to the same numbers with any units. This behavior was deprecated and has
been removed from more recently releases because it violates [transitivity][].
[transitivity]: https://en.wikipedia.org/wiki/Transitive_relation
<% end %>
The equality operators return whether or not two values are the same. They're
written `<expression> == <expression>`, which returns whether two
[expressions][] are equal, and `<expression> != <expression>`, which returns
whether two expressions are *not* equal. Two values are considered equal if
they're the same type *and* the same value, which means different things for
different types:
[expressions]: ../syntax/structure#expressions
* [Numbers][] are equal if they have the same value *and* the same units, or if
their values are equal when their units are converted between one another.
* [Strings][] are unusual in that [unquoted][] and [quoted][] strings with the
same contents are considered equal.
* [Colors][] are equal if they have the same red, green, blue, and alpha values.
* [Lists][] are equal if their contents are equal. Comma-separated lists aren't
equal to space-separated lists, and bracketed lists aren't equal to
unbracketed lists.
* [Maps][] are equal if their keys and values are both equal.
* [`true`, `false`][], and [`null`][] are only equal to themselves.
* [Functions][] are equal to the same function. Functions are compared *by
reference*, so even if two functions have the same name and definition they're
considered different if they aren't defined in the same place.
[Numbers]: ../values/numbers
[Strings]: ../values/strings
[quoted]: ../values/strings#quoted
[unquoted]: ../values/strings#unquoted
[Colors]: ../values/colors
[Lists]: ../values/lists
[`true`, `false`]: ../values/booleans
[`null`]: ../values/null
[Maps]: ../values/maps
[Functions]: ../values/functions
<% example(autogen_css: false) do %>
@debug 1px == 1px; // true
@debug 1px != 1em; // true
@debug 1 != 1px; // true
@debug 96px == 1in; // true
@debug "Helvetica" == Helvetica; // true
@debug "Helvetica" != "Arial"; // true
@debug hsl(34, 35%, 92.1%) == #f2ece4; // true
@debug rgba(179, 115, 153, 0.5) != rgba(179, 115, 153, 0.8); // true
@debug (5px 7px 10px) == (5px 7px 10px); // true
@debug (5px 7px 10px) != (10px 14px 20px); // true
@debug (5px 7px 10px) != (5px, 7px, 10px); // true
@debug (5px 7px 10px) != [5px 7px 10px]; // true
$theme: ("venus": #998099, "nebula": #d2e1dd);
@debug $theme == ("venus": #998099, "nebula": #d2e1dd); // true
@debug $theme != ("venus": #998099, "iron": #dadbdf); // true
@debug true == true; // true
@debug true != false; // true
@debug null != false; // true
@debug get-function("rgba") == get-function("rgba"); // true
@debug get-function("rgba") != get-function("hsla"); // true
===
@debug 1px == 1px // true
@debug 1px != 1em // true
@debug 1 != 1px // true
@debug 96px == 1in // true
@debug "Helvetica" == Helvetica // true
@debug "Helvetica" != "Arial" // true
@debug hsl(34, 35%, 92.1%) == #f2ece4 // true
@debug rgba(179, 115, 153, 0.5) != rgba(179, 115, 153, 0.8) // true
@debug (5px 7px 10px) == (5px 7px 10px) // true
@debug (5px 7px 10px) != (10px 14px 20px) // true
@debug (5px 7px 10px) != (5px, 7px, 10px) // true
@debug (5px 7px 10px) != [5px 7px 10px] // true
$theme: ("venus": #998099, "nebula": #d2e1dd)
@debug $theme == ("venus": #998099, "nebula": #d2e1dd) // true
@debug $theme != ("venus": #998099, "iron": #dadbdf) // true
@debug true == true // true
@debug true != false // true
@debug null != false // true
@debug get-function("rgba") == get-function("rgba") // true
@debug get-function("rgba") != get-function("hsla") // true
<% end %>