Truncate Floating-Point Numbers in Python

Code Analysis

The provided code is a Python function designed to truncate a floating-point number to a specified number of decimal places. Below is a step-by-step breakdown of its functionality:

Code Breakdown

Function Definition

def truncate_float(float_number, decimal_places):

• def is used to declare a function named truncate_float.
• The function takes two parameters:
  • float_number: The floating-point number to be truncated.
  • decimal_places: The number of decimal places to retain in the truncated result.

Multiplier Calculation

multiplier = 10 ** decimal_places

• This line calculates the multiplier by raising 10 to the power of decimal_places.
• The multiplier is used to scale the float to an integer that represents the number of significant digits.

Truncation Process

return int(float_number * multiplier) / multiplier

• float_number is multiplied by multiplier to shift the decimal places to the right.
• The product is then converted to an integer using int(), which effectively truncates the float by removing all digits after the decimal point.
• The integer is then divided by multiplier to shift the decimal places back to the left, resulting in the truncated float.

Usage Example

float3 = 3.14159
result = truncate_float(float3, 2)

print(result)

• A float float3 is assigned the value 3.14159.
• The truncate_float function is called with float3 and 2 as arguments, truncating float3 to two decimal places.
• The result is stored in the variable result and printed, which outputs 3.14.

Key Concepts

Floating-Point Arithmetic

• Floating-point numbers are used for precise calculations. This example shows a basic operation to manipulate them.

int() Function

• The int() function converts floating-point numbers to integers by truncating the decimal part, rather than rounding.

Arithmetic Operations

• The use of arithmetic operations (* and /) and exponentiation (**) demonstrates basic mathematical manipulation to achieve truncation.

Additional Examples

Truncating to Different Decimal Places

To truncate a float to three decimal places:

float3 = 3.14159
result = truncate_float(float3, 3)
print(result)  # Output: 3.141

Truncating Negative Numbers

The function also works with negative floating-point numbers:

float4 = -2.71828
result = truncate_float(float4, 2)
print(result)  # Output: -2.71

Conclusion

The truncate_float function demonstrates a straightforward method to truncate floating-point numbers to a specified number of decimal places using basic arithmetic operations. This method is efficient and easy to understand, making it a useful tool for various numerical applications.

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