Python Plus Operator (+=)

This operator combines addition and assignment in a single statement. Because Python supports mixed arithmetic, the two operands can be of different types. However, if the right-hand operand is wider, the left operand’s type is changed to that of the right operand.

The following example will help you understand how the += operator works −

a=10
b=5
print ("Augmented addition of int and int")
a+=b #equivalent to a=a+b
print ("a=",a, "type(a):", type(a))
a=10
b=5.5
print ("Augmented addition of int and float")
a+=b #equivalent to a=a+b
print ("a=",a, "type(a):", type(a))
a=10.50
b=5+6j
print ("Augmented addition of float and complex")
a+=b #equivalent to a=a+b
print ("a=",a, "type(a):", type(a))

It will produce the following output Output −

Augmented addition of int and int
a= 15 type(a): <class 'int'>
Augmented addition of int and float
a= 15.5 type(a): <class 'float'>
Augmented addition of float and complex
a= (15.5+6j) type(a): <class 'complex'>

Python Enhanced Subtraction Operator (-=)

Use the -= operator to perform subtraction and assignment in a single statement. The statement “a -= b” performs the assignment “a = a – b”. The operands can be of any numeric type. Python performs implicit type conversions for smaller objects.

a=10
b=5
print ("Augmented subtraction of int and int")
a-=b #equivalent to a=a-b
print ("a=",a, "type(a):", type(a))
a=10
b=5.5
print ("Augmented subtraction of int and float")
a-=b #equivalent to a=a-b
print ("a=",a, "type(a):", type(a))
a=10.50
b=5+6j
print ("Augmented subtraction of float and complex")
a-=b #equivalent to a=a-b
print ("a=",a, "type(a):", type(a))

It will produce the following output –

Augmented subtraction of int and float
a= 4.5 type(a): <class 'float'>
Augmented subtraction of float and complex
a= (5.5-6j) type(a): <class 'complex'>

Python Enhanced Multiplication Operator (*=)

*= operator works similarly. a*=b performs multiplication and assignment, equivalent to a=a*b. When augmented multiplication operates on two complex numbers, the multiplication rules discussed in the previous chapter apply.

a=10
b=5
print ("Augmented multiplication of int and int")
a*=b #equivalent to a=a*b
print ("a=",a, "type(a):", type(a))
a=10
b=5.5
print ("Augmented multiplication of int and float")
a*=b #equivalent to a=a*b
print ("a=",a, "type(a):", type(a))
a=6+4j
b=3+2j
print ("Augmented multiplication of complex and complex")
a*=b #equivalent to a=a*b
print ("a=",a, "type(a):", type(a))

It will produce the following output −

Augmented multiplication of int and float
a= 55.0 type(a): <class 'float'>
Augmented multiplication of complex and complex
a= (10+24j) type(a): <class 'complex'>

Python Enhanced Division Operator (/=)

The combined symbol /= acts as both a division and assignment operator, so a/=b is equivalent to a=a/b. Division of int or float operands is performed as a float. Division of two complex numbers returns a complex number. Examples of the enhanced division operator are given below.

a=10
b=5
print ("Augmented division of int and int")
a/=b #equivalent to a=a/b
print ("a=",a, "type(a):", type(a))
a=10
b=5.5
print ("Augmented division of int and float")
a/=b #equivalent to a=a/b
print ("a=",a, "type(a):", type(a))
a=6+4j
b=3+2j
print ("Augmented division of complex and complex")
a/=b #equivalent to a=a/b
print ("a=",a, "type(a):", type(a))

It will produce the following output

Augmented division of int and int
a= 2.0 type(a): <class 'float'>
Augmented division of int and float
a= 1.8181818181818181 type(a): <class 'float'>
Augmented division of complex and complex
a= (2+0j) type(a): <class 'complex'>

Python Enhanced Modulo Operator (%=)

To perform modulo and assignment in one statement, use the %= operator. Like the mod operator, this enhanced version does not support complex numbers.

a=10
b=5
print ("Augmented modulus operator with int and int")
a%=b #equivalent to a=a%b
print ("a=",a, "type(a):", type(a))
a=10
b=5.5
print ("Augmented modulus operator with int and float")
a%=b #equivalent to a=a%b
print ("a=",a, "type(a):", type(a))

will produce the following output −

Augmented modulus operator with int and int
a= 0 type(a): <class 'int'>
Augmented modulus operator with int and float
a= 4.5 type(a): <class 'float'>

Python Enhanced Exponentiation Operator (**=)

The **= operator raises “a” to the power “b” and assigns the result to “a.” Here are some examples −

a=10
b=5
print ("Augmented exponent operator with int and int")
a**=b #equivalent to a=a**b
print ("a=",a, "type(a):", type(a))
a=10
b=5.5
print ("Augmented exponent operator with int and float")
a**=b #equivalent to a=a**b
print ("a=",a, "type(a):", type(a))
a=6+4j
b=3+2j
print ("Augmented exponent operator with complex and complex")
a**=b #equivalent to a=a**b
print ("a=",a, "type(a):", type(a))

will produce the following output −

Augmented exponent operator with int and int
a= 100000 type(a): <class 'int'>
Augmented exponent operator with int and float
a= 316227.7660168379 type(a): <class 'float'>
Augmented exponent operator with complex and complex
a= (97.52306038414744-62.22529992036203j) type(a): <class 'complex'>

Python Enhanced Floor Division Operator (//=)

To perform floor division and assignment in a single statement, use the //= operator. a//=b is equivalent to a=a//b. This operator cannot be used with complex numbers.

a=10
b=5
print ("Augmented floor division operator with int and int")
a//=b #equivalent to a=a//b
print ("a=",a, "type(a):", type(a))
a=10
b=5.5
print ("Augmented floor division operator with int and float")
a//=b #equivalent to a=a//b
print ("a=",a, "type(a):", type(a))

It will produce the following output:

Augmented floor division operator with int and int
a= 2 type(a): <class 'int'>
Augmented floor division operator with int and float
a= 1.0 type(a): <class 'float'>