# 变量（Variables）

Variables are pieces of data received from the app. They are provided by the developer of the app and may be interpolated into the translation with placeables. Variables can dynamically change as the user is using the localized product.

Variables are referred to via the $variable-name syntax: welcome = Welcome, {$user }!
unread-emails = { $user } has {$email-count } unread emails.


For instance, if the current user’s name is Jane and she has 5 unread emails, the above translations will be displayed as:

Welcome, Jane!


There are all kinds of external data that might be useful in providing a good localization: user names, number of unread messages, battery level, current time, time left before an alarm goes off, etc. Fluent offers a number of features designed to make working with variables convenient.

## Variants and Selectors

In some languages, using a number in the middle of a translated sentence will require proper plural forms of words associated with the number. In Fluent, you can define multiple variants of the translation, each for a different plural category.

## Implicit Formatting

Numbers and dates are automatically formatted according to your language’s formatting rules. Consider the following translation:

# $duration (Number) - The duration in seconds. time-elapsed = Time elapsed: {$duration }s.


For the $duration variable value of 12345.678, the following message will be displayed in the product, assuming the language is set to British or American English. Note the use of comma as the thousands separator. Time elapsed: 12,345.678s.  In Canadian English, however, the result would be: Time elapsed: 12 345.678s.  ## Explicit Formatting In some cases the localizer might want to have a greater control over how a number or a date is formatted in text. Fluent provides built-in functions for this purpose. #$duration (Number) - The duration in seconds.
time-elapsed = Time elapsed: { NUMBER($duration, maximumFractionDigits: 0) }s.  For the same value of $duration as above, the result will look like the following for American and British English:

Time elapsed: 12,345s.