Python complex() Function

The complex() function returns a complex number by specifying a real number and an imaginary number.

It can also convert a string to a complex number.

note

The complex number is returned in the form of real + imaginary, where the imaginary part is followed by a j.

Syntax

complex(real,imaginary)

complex() Parameters

Python complex() function parameters:

Parameter	Condition	Description
real	Optional	The real part of the complex number. Default is 0.
imaginary	Optional	The imaginary part of the complex number. Default is 0.

complex() Return Value

Python complex() function returns a complex number.

Examples

Create complex numbers

You can create a complex number by specifying real and imaginary parts.

x = complex(3, 2)
print(x)            # Output: (3+2j)

x = complex(-3, 2)
print(x)            # Output: (-3+2j)

x = complex(3, -2)
print(x)            # Output: (3-2j)

output

(3+2j)
(-3+2j)
(3-2j)

Create complex numbers by omitting arguments

If you omit one of the arguments, it is assumed to be 0, because the default value of real and imaginary parameters is 0.

# omit imaginary part
x = complex(3)
print(x)            # Output:(3+0j)

# omit real part
x = complex(0, 4)
print(x)            # Output: 4j

# omit both
x = complex()
print(x)            # Output: 0j

Create complex number without using complex() function

It's possible to create a complex number without using complex() function: you have to put j or J after a number.

a = 2+3j
print('a =',a)
print('Type of a is',type(a))

b = -2j
print('b =',b)
print('Type of b is',type(a))

c = 0j
print('c =',c)
print('Type of c is',type(c))

output

a = (2+3j)
Type of a is <class 'complex'>
b = (-0-2j)
Type of b is <class 'complex'>
c = 0j
Type of c is <class 'complex'>