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89 lines
3.0 KiB
Plaintext
89 lines
3.0 KiB
Plaintext
---
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title: Numbers
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introduction: >
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Numbers in Sass have two components: the number itself, and its units. For
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example, in `16px` the number is `16` and the unit is `px`. Numbers can have
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no units, and they can have complex units. See [Units](#units) below for more
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details.
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---
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<% example(autogen_css: false) do %>
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@debug 100; // 100
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@debug 0.8; // 0.8
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@debug 16px; // 16px
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@debug 5px * 2px; // 10px*px (read "square pixels")
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===
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@debug 100 // 100
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@debug 0.8 // 0.8
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@debug 16px // 16px
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@debug 5px * 2px // 10px*px (read "square pixels")
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<% end %>
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Sass numbers support the same formats as CSS numbers, including [scientific
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notation][], which is written with an `e` between the number and its power
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of 10. Because support for scientific notation in browsers has historically
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been spotty, Sass always compiles it to fully expanded numbers.
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[scientific notation]: https://en.wikipedia.org/wiki/Scientific_notation
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<% example(autogen_css: false) do %>
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@debug 5.2e3; // 5200
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@debug 6e-2; // 0.06
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===
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@debug 5.2e3 // 5200
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@debug 6e-2 // 0.06
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<% end %>
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<% heads_up do %>
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Sass doesn't distinguish between whole numbers and decimals, so for example `5
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/ 2` returns `2.5` rather than `2`. This is the same behavior as JavaScript,
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but different than many other programming languages.
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<% end %>
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<%= partial 'documentation/snippets/number-units' %>
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## Precision
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<% impl_status dart: true, libsass: false, ruby: '3.5.0', feature: '10 Digit Default' do %>
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LibSass and older versions of Ruby Sass default to 5 digits of numeric
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precision, but can be configured to use a different number. It's recommended
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that users configure them for 10 digits for greater accuracy and
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forwards-compatibility.
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<% end %>
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Sass numbers support up to 10 digits of precision after the decimal point. This
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means a few different things:
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* Only the first ten digits of a number after the decimal point will be included
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in the generated CSS.
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* Operations like [`==`][] and [`>=`][] will consider two numbers equivalent if
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they're the same up to the tenth digit after the decimal point.
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* If a number is less than `0.0000000001` away from an integer, it's considered
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to be an integer for the purposes of functions like [`list.nth()`][] that require
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integer arguments.
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[`==`]: ../operators/equality
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[`>=`]: ../operators/relational
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[`list.nth()`]: ../modules/list#nth
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<% example(autogen_css: false) do %>
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@debug 0.012345678912345; // 0.0123456789
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@debug 0.01234567891 == 0.01234567899; // true
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@debug 1.00000000009; // 1
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@debug 0.99999999991; // 1
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===
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@debug 0.012345678912345 // 0.0123456789
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@debug 0.01234567891 == 0.01234567899 // true
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@debug 1.00000000009 // 1
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@debug 0.99999999991 // 1
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<% end %>
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<% fun_fact do %>
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Numbers are rounded to 10 digits of precision *lazily* when they're used in a
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place where precision is relevant. This means that math functions will work
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with the full number value internally to avoid accumulating extra rounding
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errors.
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<% end %>
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