# Swift Operators

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This tutorial belongs to the Swift series

We can use a wide set of operators to operate on values.

We can divide operators in many categories. The first is the number of targets: 1 for unary operators, 2 for binary operators or 3 for the one and only ternary operator.

Then we can divide operators based on the kind of operation they perform:

• assignment operator
• arithmetic operators
• compound assignment operators
• comparison operators
• range operators
• logical operators

plus some more advanced ones, including nil-coalescing, ternary conditional, overflow, bitwise and pointwise operators.

Note: Swift allows you to create your own operators and define how operators work on your types you define.

### Assignment operator

The assignment operator is used to assign a value to a variable:

``````var age = 8
``````

Or to assign a variable value to another variable:

``````var age = 8
var another = age
``````

### Arithmetic operators

Swift has a number of binary arithmetic operators: `+`, `-`, `*`, `/` (division), `%` (remainder):

``````1 + 1 //2
2 - 1 //1
2 * 2 //4
4 / 2 //2
4 % 3 //1
4 % 2 //0
``````

`-` also works as a unary minus operator:

``````let hotTemperature = 20
let freezingTemperature = -20
``````

`+` is also used to concatenate String values:

``````"Roger" + " is a good dog"
``````

### Compound assignment operators

The compound assignment operators combine the assignment operator with arithmetic operators:

• `+=`
• `-=`
• `*=`
• `/=`
• `%=`

Example:

``````var age = 8
age += 1
``````

### Comparison operators

Swift defines a few comparison operators:

• `==`
• `!=`
• `>`
• `<`
• `>=`
• `<=`

You can use those operators to get a boolean value (`true` or `false`) depending on the result:

``````let a = 1
let b = 2

a == b //false
a != b //true
a > b // false
a <= b //true
``````

### Range operators

Range operators are used in loops. They allow us to define a range:

``````0...3 //4 times
0..<3 //3 times

0...count //"count" times
0..<count //"count-1" times
``````

Here’s a sample usage:

``````let count = 3
for i in 0...count {
//loop body
}
``````

### Logical operators

Swift gives us the following logical operators:

• `!`, the unary operator NOT
• `&&`, the binary operator AND
• `||`, the binary operator OR

Sample usage:

``````let condition1 = true
let condition2 = false

!condition1 //false

condition1 && condition2 //false
condition1 || condition2 //true
``````

Those are mostly used in the `if` conditional expression evaluation:

``````if condition1 && condition2 {
//if body
}
``````
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