Rust If .. Else Conditions

Conditions and If..Else

You have already learned that Rust supports the usual logical conditions from mathematics:

• Less than: a < b
• Less than or equal to: a <= b
• Greater than: a > b
• Greater than or equal to: a >= b
• Equal to a == b
• Not Equal to: a != b

You can use these conditions to perform different actions for different decisions.

Rust has the following conditional statements:

• Use if to specify a block of code to be executed, if a specified condition is true
• Use else to specify a block of code to be executed, if the same condition is false
• Use else if to specify a new condition to test, if the first condition is false
• Use switch to specify many alternative blocks of code to be executed

Note: Unlike many other programming languages, if..else can be used as a statement or as an expression (to assign a value to a variable) in Rust. See an example at the bottom of the page to better understand it.

if

Use if to specify a block of code to be executed if a condition is true.

You can also test variables:

if...else

If the condition is not true, you can use else to run different code:

else if

You can check multiple conditions using else if:

Using if as an Expression

In Rust, if...else can also be used as an expression.

This means you can assign the result of an if to a variable:

When using if as an expression, you must include else . This ensures the result always has a value.

Simplified Syntax

If each block only contains one line, you can remove the curly braces {} and write it in a shorter way:

Note: The value from if and else must be the same type, like two pieces of text or two numbers (in our example, both are strings).

Tip: This example works similarly to the ternary operator (short-hand if...else) in languages like Java or C.