红宝石 |数学 log()函数

Ruby 中的log()函数返回X的对数值。第二个参数是用户给出的对数值返回的底数。如果未给出，则默认基数为e 。

Syntax: Math.log(X, base)

Parameter: The function takes one mandatory parameter X whose logarithm value is to be returned and a non-mandatory parameter base, to whose base is the logarithm.

Return Value: The function returns the logarithm value of X.

示例 1 ：

# Ruby program for log() function 
  
# Assigning values
val1 = 213
val2 = 256
base2 = 2
  
val3 = 27 
base3 = 3
  
val4 = 100 
base4 = 10
  
# Prints the value returned by log() 
puts Math.log(val1)
  
puts Math.log(val2, base2)
  
puts Math.log(val3, base3)
  
puts Math.log(val4, base4)

输出：

5.3612921657094255
8.0
3.0
2.0

示例 2 ：

# Ruby program for log() function 
  
# Assigning values
val1 = 10
  
val2 = 256
base2 = 4
  
val3 = 27 
base3 = 10
  
val4 = 105 
base4 = 7
  
# Prints the value returned by log() 
puts Math.log(val1)
  
puts Math.log(val2, base2)
  
puts Math.log(val3, base3)
  
puts Math.log(val4, base4)

输出：

2.302585092994046
4.0
1.4313637641589871
2.3916625094004957

参考：https://devdocs.io/ruby~2.5/math#method-c-log