Python's number types and their techniques

Number types in Python

int
float
fractions.Fraction
decimal.Decimal

Number rounding and rounding

int(f): round off the decimal part and keep only the integer part, so int(-3.8) The result is -3
math.trunc(f): same as int(f)
round(f, digits): rounded to digits decimal place.
math.floor(f)
math.ceil(f)

Make a judgment

math.isinf()
math.isfinite()
math.isnan()
float.is_integer()

How to calculate power

The following 3 methods all represent square root
math.sqrt(144)
144**0.5
pow(144,0.5)

base conversion

int(s,base): The first parameter is a number representing a number String, the second parameter is base. int('111',2) means converting the binary string '111' into an integer.
oct, hex, bin: Convert a number to the corresponding base string representation, so the results are all str instead of numbers.

0xfe, 0b11111110, 0o376 and 254 are all the same inside Python, representing the number 254. There is no difference between these representations for Python. '0xfe' is just a string. If you need to convert it to an integer, you need to use the int function, int('0xfe',16).

Commonly used modules

math

are used to do some mathematical operations

random

are used to generate some random numbers.
This module provides a lot of functions, which is particularly useful.
random.random(): Generate a random number between [0,1)
random.randint(min, max): Generate a random integer between [min, max)
random.choice(iterable): From iterable Randomly select an element from the object and return it.
random.sample(iterable, k): Randomly select k unique elements from iterable and return them in the form of an array.
random.randrange(start, stop, step): Step by step in [start, stop) to randomly generate an element.
random.shuffle(l): Randomly shuffle the sequence in place and return None. It's important to note that this works in situ.

decimal

If you need the results to be accurate, you can use this module.
decimal.Decimal(str): used to create a Decimal object.
decimal.getcontext().PRec=n: Set the number of decimal points.

fractions

If you need the results to be accurate, you can use this module.
x=fractions.Fraction(1,3)
y=fractions.Fraction(0.25)
z=fractions.Fraction(*(3.25.as_integer_ratio()))

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