python mathの基本的な使い方
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Constants of the math Module
Arithmetic Functions
math.ceil() will return the smallest integer value that is greater than or equal to the given number
floor() will return the closest integer value that is less than or equal to the given number. This function behaves opposite to ceil().
Truncate Numbers With trunc()
When you get a number with a decimal point, you might want to keep only the integer part and eliminate the decimal part.
Find the Closeness of Numbers With Python isclose()
Power Functions
The reason behind the efficiency of math.pow() is the way that it’s implemented. It relies on the underlying C language
Logarithmic Functions
other functions Convert Angle Values Calculate the Sum of Iterables Calculate the Square Root Calculate the Greatest Common Divisor
ref: https://realpython.com/python-math-module/#getting-to-know-the-python-math-module
>>> import math
>>> math.pi, math.tau
(3.141592653589793, 6.283185307179586)
>>> math.e
2.718281828459045
>>> math.inf
inf
>>> x = 1e10
>>> math.inf > x
True
>>> math.nan
nan
Arithmetic Functions
>>> math.factorial(5)
120
math.ceil() will return the smallest integer value that is greater than or equal to the given number
>>> math.ceil(-2.2), math.ceil(3.3)
(-2, 4)
floor() will return the closest integer value that is less than or equal to the given number. This function behaves opposite to ceil().
>>> math.floor(4.4), math.floor(-2.2)
(4, -3)
Truncate Numbers With trunc()
When you get a number with a decimal point, you might want to keep only the integer part and eliminate the decimal part.
>>> math.trunc(22.12)
22
Find the Closeness of Numbers With Python isclose()
>>> math.isclose(4,5,rel_tol=0.1)
False
>>> math.isclose(4,5,abs_tol=1)
True
Power Functions
>>> math.pow(5, 2)
25.0
>>> math.pow(5, 2.4), pow(5, 2.4)
(47.59134846789696, 47.59134846789696)
import timeit
>>> timeit.timeit("10 ** 308")
0.7564038369999999
>>> timeit.timeit("pow(10, 308)")
0.8013294880000004
>>> timeit.timeit("math.pow(10, 308)", setup="import math")
0.1495649570000004
The reason behind the efficiency of math.pow() is the way that it’s implemented. It relies on the underlying C language
>>> math.exp, math.exp(2)
(<function math.exp(x, /)>, 7.38905609893065)
Logarithmic Functions
>>> math.log(4) # base of e
1.3862943611198906
>>> math.log(math.pi, 2) # base of pi (first argument)
1.651496129472319
other functions
ref: https://realpython.com/python-math-module/#getting-to-know-the-python-math-module