Python Data Conversion

In Python, sometimes you need to change the type of a number. This process is called type conversion. It’s useful when working with different types of values in mathematical operations or data processing.

Converting int → float → complex

Let’s begin with an integer and convert it into other types:

				
					score = -18

as_float = float(score)       # Convert to float
as_complex = complex(score)   # Convert to complex

print("Float:", as_float)       # Output: -18.0
print("Complex:", as_complex)   # Output: (-18+0j)

The float() function adds a decimal point, while complex() adds an imaginary part +0j.

Converting float → int → complex

You can also convert a float to an integer, or a complex number:

				
					price = 49.75

as_int = int(price)            # Converts to whole number (drops decimal part)
as_complex = complex(price)    # Adds imaginary part

print("Integer:", as_int)        # Output: 49
print("Complex:", as_complex)    # Output: (49.75+0j)

Note: int() doesn’t round; it simply truncates the decimal part.

Complex to int or float?

Python does not allow direct conversion from complex to int or float, and trying to do so will result in an error.

				
					z = 3 + 2j
# int(z) or float(z) will raise: TypeError

To convert a complex number, you’ll first need to extract its real part:

				
					real_part = int(z.real)
print("Real as int:", real_part)  # Output: 3

Summary

Use float(x) to convert an integer to a float.
Use complex(x) to turn a number into a complex type.
Use int(x) to convert a float to an integer (truncates decimal).
You cannot directly convert complex numbers to int or float.