How to express logarithmic function in python

log() returns the natural logarithm of x. math.log(x) is equivalent to ln(x) in mathematics, x>0, find the logarithm with the base e, e = 2.718281828459; math.log10(x) is equivalent to lg(x) in mathematics, x>0, find the logarithm with base 10. The base can be set by log(x[, base]), for example, log(x, 10) represents the logarithm with base 10.

Syntax

The following is the syntax of the log() method:

import math
math.log(x[, base])

Note: log() is If it cannot be accessed directly, you need to import the math module and call this method through a static object.

Parameters

x -- Numeric expression. base -- optional, base, default is e.

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Return value

Returns the natural logarithm of x, x>0 .

Example

The following shows an example of using the log() method:

#!/usr/bin/python
# -*- coding: UTF-8 -*-
import math   # 导入 math 模块
print "math.log(100.12) : ", math.log(100.12)
print "math.log(100.72) : ", math.log(100.72)
print "math.log(119L) : ", math.log(119L)
print "math.log(math.pi) : ", math.log(math.pi)# 设置底数
print "math.log(10,2) : ", math.log(10,2)

The output result after running the above example is:

math.log(100.12) :  4.60636946656
math.log(100.72) :  4.61234438974
math.log(119L) :  4.77912349311
math.log(math.pi) :  1.14472988585
math.log(10,2) :  3.32192809489

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