5 Best Ways to Convert Python Complex Numbers to Real Numbers

Often in programming with Python, you might encounter complex numbers and require their real components for further calculations. A complex number in Python is expressed as a + bj, where a is the real part, and b is the imaginary part. This article outlines methods to extract the real part, a, from a complex number. For instance, given the input 3+4j, the desired output is 3.0.

Method 1: Using the real Attribute

Every complex number in Python has a real attribute that provides the real part of the number. It’s the most straightforward approach to accessing the real component of a complex number: simply call your_complex_number.real, and it returns a floating-point value.

Here’s an example:

complex_num = 3 + 4j
print(complex_num.real)

Output:

3.0

In this code snippet, we define a complex number complex_num and print its real part. Accessing the real attribute provides the real component as a float.

Method 2: Using the abs() Function

The abs() function in Python returns the magnitude of the complex number, which is different from the real part. It’s calculated as the square root of the sum of squares of the real part and the imaginary part. However, if the imaginary part is zero, the absolute value will give you the real part.

Here’s an example:

complex_num = 3 + 0j
print(abs(complex_num))

Output:

3.0

Here, abs(complex_num) returns the absolute value of the real part since the imaginary part is zero. This method is rarely used for extracting the real part as it requires the imaginary part to be zero.

Method 3: Real Component with Type Conversion

You can convert the real attribute to a different type to remove any imaginary component. For example, you can convert the real part to an integer using the int() function if you need an integer value and know the imaginary part is zero.

Here’s an example:

complex_num = 3 + 0j
real_part = int(complex_num.real)
print(real_part)

Output:

3

Calling int(complex_num.real) converts the real part to an integer. This is useful if you need to ensure the real part is an integer type, but it can lead to loss of information if not used carefully.

Method 4: Using the cmath Module

The cmath module provides access to mathematical functions for complex numbers. While not directly necessary for extracting the real part, it is useful to know for complete handling of complex numbers.

Here’s an example:

import cmath
complex_num = 3 + 4j
real_part = cmath.phase(complex_num)
print(real_part)

Output:

0.9272952180016122

In this code, cmath.phase(complex_num) returns the phase angle, which is not the real part but often useful in operations involving polar coordinates.

Bonus One-Liner Method 5: Extract with a Lambda Function

Python’s lambda functions can be used to create an inline function that extracts the real part of a complex number for quick operations.

Here’s an example:

get_real = lambda x: x.real
print(get_real(3 + 4j))

Output:

3.0

The lambda function get_real is defined to take a complex number x and return its real attribute. It’s a concise one-liner that can be used whenever you need to map or filter real parts from a sequence of complex numbers.

Summary/Discussion

• Method 1: real Attribute. The easiest and most direct approach. Always returns a float.
• Method 2: abs() Function. Only useful when the imaginary part is zero. Uncommon for extracting real parts.
• Method 3: Type Conversion. Allows for conversion to different numeric types. Can cause loss of information if the conversion discards important details.
• Method 4: cmath Module. Not used for extracting the real part directly but offers comprehensive complex number functions.
• Bonus Method 5: Lambda Function. Quick and inline, good for functional programming style. It’s more of a stylistic choice than a practical one.