python study manual: Chapter 5 - Digital

Numeric constants

python supports the following types of digital

• Integer (positive and negative integers): python integer having infinite precision
• Float
• 0x123 hexadecimal number
• Octal number 0o123

• Binary 0b1010101

  The basic numeric constants

• 1234,-2,0,999999
• 1.23,1., 3.14e-10,4E210,4.0e + 210 # 4e210 is the 4 * 10 ^ 210
• Plural: 3 + 4j
• In case the judge sentences the wrong stop, will not judge the statement following
• Formatting of decimal places

print('{:.2}'.format(12.11234)) 1.2e+01

division

• x / y: traditional division, the fractional part will be retained
• x // y: floor divider, the fractional part will be removed
• x% y: modulo division, modulo

In addition to the cut-off difference except the floor

• math.floor (-5/2)> -3 increased fractional part discarded

• math.trunc (-5/2)> -2 simply to retain the integer part

  Special hexadecimal number

• oct (64)> 0100 is converted into a string of octal
• hex (64)> 0x40 converted to a string of 16 hexadecimal
• bin (64)> 0b1000000 converted to binary string

• int (x, y)> y x to the hexadecimal number, y in [2,8,10,16]

  Bit operating

• << similar exponentiation x = 1, x << 2> x = 4

• Similar to the square root x = 4, x >> 2, x = 2

  Some methods of math

• math.sin
• Math.PI
• math.e
• math.sqrt () square root
• power pow 4 (2,4) 2
• ads () absolute value
• sum()

• max&min

random module

import random
random.random() #随机生成一个数字
random.choice([1,2,3,4,5]) #从列表中随机选出一个数字
random.randint(1,10) #从1到10随机产生一个数字，括号左右均包括