The complex() function returns a complex number based on a given string or a given real and imaginary part. It is also possible to declare a complex number without the complex() function by adding j or J after a number.
Create a complex number with complex()
To create a complex number with the complex() function we can use a string or a given real and imaginary part.
# create a complex number with complex()
myComplex = complex(2, 5)
print(myComplex)
The complex number 2+5j is returned.
(2+5j)
We can check the type of the created number by using type().
# check the type of complex
myComplex = complex(2, 5)
print(type(myComplex))
The type of the complex variable is returned and we can confirm that a complex number was created.
<class 'complex'>
The complex() function is also useful to convert a string containing a complex number to a complex type.
# convert string to complex number
myComplex = complex('2-5j')
print(myComplex)
The complex number is returned.
(2-5j)
Create complex number without complex()
To create a complex number in Python without the complex() function it needs to end with j or J.
myComplex = 2-5j
print(myComplex)
The complex number is returned.
(2-5j)
complex() syntax
The syntax of the complex function() is:
complex(real, [imaginary])
complex() arguments
The complex() function takes 1 or 2 arguments:
- required: real, the real part of a complex number.
- optional: imaginary, the imaginary part of a complex number
If the first argument is a string, the second argument is optional. The string should be in the format [real](+/-)[imaginary]j.
complex() return value
The complex() function returns a complex number of the type complex.
If the passed arguments don't represent a valid complex number, a ValueError exception is raised.
ValueError: complex() arg is a malformed string