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Python - math.log() method example

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Created by:

Keisha-Acosta

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The math.log() method returns the natural logarithm (base e) of a number.

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import math
​
print(math.log(1))      # 0
print(math.log(7))      # 1.9459101490553132
print(math.log(10))     # 2.3025850929940460
print(math.log(100))    # 4.6051701859880920
print(math.log(1000))   # 6.9077552789821370
​
print(math.e)  # 2.718281828459045
​
# Logarithm with custom base is placed in the below example.

The math.log() method is presented on the following chart:

math.log(x) function visualization - Python math module.

1. Documentation

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Syntax	xxxxxxxxxx 1 math.log(x, newBase)
Parameters	`x`- value in the range `0` to `infinitive`. `newBase` - logarithm base.
Result	`number` value calculated as ln(x) mathematical function. If `x` is negative it returns ValueError. If `x` is equal to `0` it returns ValueError. If `x` is equal to `infinity` it returns `infinity`.
Description	`log` is a method that takes one parameter and returns an approximation of the ln(x) function (natural logarithm function - logarithm with base `e`).

2. Logarithm with custom base example

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This example shows a logarithmic function calculation with its own base.

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import math
​
​
def calculate_logarithm(log_base, x):
    a = math.log(x)
    b = math.log(log_base)
    return a / b
​
​
# Logarithm with custom base:
#                          base     x              y
print(calculate_logarithm( 2,       2       ) )  # 1.0
print(calculate_logarithm( 2,       4       ) )  # 2.0
print(calculate_logarithm( math.e,  math.e  ) )  # 1.0
print(calculate_logarithm( 3,       9       ) )  # 2.0
print(calculate_logarithm( 3,       81      ) )  # 4.0
print(calculate_logarithm( 10,      10      ) )  # 1.0