Swift Tutorial Swift References

Swift - Operators



Operators are used to perform operation on a single operand or two operands. Operators in Swift can be categorized as follows:

  • Arithmetic operators
  • Assignment operators
  • Comparison operators
  • Logical operators
  • Bitwise operators
  • Range operators
  • Miscellaneous operators

Swift Arithmetic operators

Arithmetic operators are used to perform arithmetic operations on two operands.

OperatorNameDescription
+AdditionAdd two values
-SubtractionSubtract one value from another
*MultiplicationMultiply two values
/DivisionDivide one value by another
%ModuloReturns remainder of division operation

Example

Swift Assignment operators

Assignment operators are used to assign values of right hand side expression to left hand side operand.

OperatorExpressionEquivalent toDescription
=a = 5a = 5Example
+=a += ba = a + b
-=a -= ba = a - b
*=a *= ba = a * b
/=a /= ba = a / b
%=a %= ba = a % b
&=a &= ba = a & bMore Info
|=a |= b a = a | bMore Info
^=a ^= b a = a ^ bMore Info
>>=a >>= ba = a >> bMore Info
<<=a <<= ba = a << bMore Info

Swift Comparison operators

Comparison operators are used to compare values of two operands. It returns true when values matches and returns false when values does not match.

OperatorDescription
==Equal
!= Not equal
>Greater than
<Less than
>=Greater than or equal to
<=Less than or equal to

Example

Swift Logical operators

Logical operators are used to combine two or more conditions.

Operator NameDescription
&& Logical ANDReturns true when all conditions are true
||Logical ORReturns true when any of the conditions is true
!Logical NOTReturns true when given conditions is not true

More Info

Swift Bitwise operators

Bitwise operators are used to perform bitwise operations on two operands.

OperatorNameDescriptionMore Info
&ANDReturns 1 if both bits at the same position in both operands are 1, else returns 0.More Info
|ORReturns 1 if one of two bits at the same position in both operands is 1, else returns 0.More Info
^XORReturns 1 if only one of two bits at the same position in both operands is 1, else returns 0.More Info
~NOTReverse all the bits.More Info
>>Right shiftThe left operand is moved right by the number of bits present in the right operand.More Info
<<Left shiftThe left operand value is moved left by the number of bits present in the right operand.More Info

Swift Range operators

The table below describes other operators supported by Swift:

OperatorDescriptionExample
Closed Range Operator(a...b)
Defines a range that runs from a to b, and includes the values a and b. The value of a must not be greater than b.
Example
Half-Open Range Operator(a..<b)
Defines a range that runs from a to b, but does not include b. The value of a must not be greater than b.
One-Sided Ranges(a...)
Defines a range that runs from a to end of elements.
(...a)
Defines a range starting from start to a.

Swift Miscellaneous operators

The table below describes other operators supported by Swift:

OperatorDescription
ternary operator (?:)Returns one of the two values based on value of boolean expression.
Nil-Coalescing Operator (??)Returns right-hand side operand when left-hand side operand is nil, otherwise returns left-hand side operand.
Unary plusReturns the value it operates on, without any change. For example: if A = 10 then +A gives 10.
Unary minusReturns the value it operates on with sign changed. For example: if A = -10 then -A gives 10.

Swift Operators Precedence

Operator precedence (order of operations) is a collection of rules that reflect conventions about which procedures to perform first in order to evaluate a given expression.

For example, multiplication has higher precedence than addition. Thus, the expression 1 + 2 × 3 is interpreted to have the value 1 + (2 × 3) = 7, and not (1 + 2) × 3 = 9. When exponent is used in the expression, it has precedence over both addition and multiplication. Thus 3 + 52 = 28 and 3 × 52 = 75.

Swift has predefined - prefix, postfix and infix operators. The prefix operators are as follows:

  • ! Logical NOT
  • .! Pointwise logical NOT
  • ~ Bitwise NOT
  • + Unary plus
  • - Unary minus
  • ..< Half-open range
  • ... Closed range

The postfix operators are as follows:

  • ... Range

The following table lists the precedence and associativity of Swift infix operators. Operators are listed top to bottom, in descending precedence. Operators with higher precedence are evaluated before operators with relatively lower precedence. When operators have the same precedence, associativity of the operators determines the order in which the operations are performed.

PrecedenceOperatorDescriptionAssociativity
16<<  >>Bitwise left shift and right shiftnon-associative
&<<  &>>Bitwise left shift and right shift, ignoring overflow
15*  /  %Multiplication, Division, RemainderLeft to Right
&Bitwise AND
&*Multiply with overflow
14+  -Addition, Subtraction
|  ^Bitwise OR, Bitwise XOR
&+  &-Add with overflow, Subtract with overflow
13..<  ...Half-open range, Closed rangenon-associative
12isType checkLeft to Right
as  as?  as!Type cast
11??Nil coalescing operatorRight to Left
10<  <=  >  >=Less than, Less than or equal, Greater than, and Greater than or equalnon-associative
9==  !=Equality and Inequality
8===  !==Identical and Not identical
7~=Pattern match
6.<  .<=  .>  .>=Pointwise less than, Pointwise less than or equal, Pointwise greater than, and Pointwise greater than or equal
5.==  .!=Pointwise equality and Pointwise inequality
4&&  .&Logical AND, Pointwise bitwise ANDLeft to Right
3||  .|  .^Logical OR, Pointwise bitwise OR, Pointwise bitwise XOR
2a?b:cConditional (ternary) operatorRight to Left
1=Direct assignment
+=  -=  *=  /=  %=Compound assignment by sum, difference, product, quotient and remainder
<<=  >>=Compound assignment by Bitwise left shift and right shift
&=  ^=  |=Compound assignment by Bitwise AND, XOR and OR
&+=  &-=  &*=Add, Subtract and Multiply with overflow and assign
&<<=  &>>=Assign by Left bit shift and Right bit shift ignoring overflow
.&=  .|=  .^=Assign by Pointwise bitwise AND, Pointwise bitwise OR, Pointwise bitwise XOR

5