Python complex() Function

Last Updated : 15 Nov, 2023

Python complex() function returns a complex number ( real + imaginary) example (5+2j) when real and imaginary parts are passed, or it also converts a string to a complex number.

Python complex() Function Syntax

Syntax: complex ([real[, imaginary]])

real [optional]: numeric type (including complex). It defaults to zero.

imaginary [optional]: numeric type (including complex) .It defaults to zero.

Return: Returns a complex number in the form of (real + imaginary) example (5+2j)

Note: If the first parameter that passed is a string then the second parameter shouldn’t be passed else will raise a TypeError. The string must not contain whitespace around the + or – operator else it will raise ValueError in Python.

complex() Function in Python

In this example, we will see how to create a complex number in Python using complex() function.

Python3

print(complex(1, 2))

Output:

(1+2j)

complex() With Integer and Float Type Parameters

In this example, we are using complex() to create a complex number in Python with integer and float type parameters.

Python3

# numeric type
# nothing is passed
z = complex()
print("complex() with no parameters:", z)
 
 
# integer type
# passing first parameter only
complex_num1 = complex(5)
print("Int: first parameter only", complex_num1)
 
# passing both parameters
complex_num2 = complex(7, 2)
print("Int: both parameters", complex_num2)
 
# float type
# passing first parameter only
complex_num3 = complex(3.6)
print("Float: first parameter only", complex_num3)
 
# passing both parameters
complex_num4 = complex(3.6, 8.1)
print("Float: both parameters", complex_num4)
print()
 
# type
print(type(complex_num1))

Output

Nothing is passed 0j
Int: first parameter only (5+0j)
Int: both parameters (7+2j)
Float: first parameter only (3.6+0j)
Float: both parameters (3.6+8.1j)

<class 'complex'>

complex() With String Type Parameters of the Numeric Form

In this example, we are using complex() to create a complex number in Python with String Type Parameters of the Numeric Form.

Python3

# string
# only first parameter is to be passed
z1 = complex("7")
print(z1)
 
print()
z2 = complex("2", "3")
 
# This will raise TypeError"
print(z2)

Output

complex() with String Type Parameters of Complex Number Form

In this example, we are using complex() to create a complex number in Python with string type parameters of Complex Number form.

Python3

# string
# only first parameter is passed
z1 = complex("7+17j")
print(z1)
 
print()
z2 = complex("7 + 17j")
 
# This will raise Valueerror
# due to spaces around operator
print(z2)