method
log
v1_9_3_392 -
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- Class:
Math
log(p1, p2 = v2)public
Returns the natural logarithm of numeric. If additional second argument is given, it will be the base of logarithm.
Math.log(1) #=> 0.0 Math.log(Math::E) #=> 1.0 Math.log(Math::E**3) #=> 3.0 Math.log(12,3) #=> 2.2618595071429146
1Note
Any base logarithm
Using basic arithmetic you can get logarithm with any base:
def log_with_base base, num
Math.log(num) / Math.log(base)
end
Examples:
>> log_with_base 2, 10
=> 3.32192809488736
>> log_with_base 2, 2
=> 1.0
>> log_with_base 2, 4
=> 2.0
>> log_with_base 2, 16
=> 4.0
>> log_with_base 4, 16
=> 2.0
