>>> no = 74
>>> year = 1984
>>> s = "Soldier %04d, welcome to %d." % (no, year)
>>> s
'Soldier 0074, welcome to 1984.'
# d代表十进制数据，4是最小输出字符数，用0填充。

>>> s1 = "nice"
>>> s2 = s1
>>> s1 += " tits"
>>> s2 += " boobs"
>>> s1
'nice tits'
>>> s2
'nice boobs'

import copy
# 一维数组可以使用list()或copy()
a = [1, 2, 3]
b = list(a)
b = copy.copy(a)
# 高维数组必须使用deepcopy()
a = [[1, 2], [3, 4]]
b = copy.deepcopy(a)

>>> type(True)
<class 'bool'>
>>> type(1)
<class 'int'>
>>> 1 == True
True
>>> 1 ^ True
0
>>> 0 ^ True
1

>>> li = [[2, 6.6], [4, 5]]
>>> li.sort(key=lambda e:e[1])
>>> li
[[4, 5], [2, 6.6]]
>>> li.sort(key=lambda e:e[1], reverse=True)
>>> li
[[2, 6.6], [4, 5]]
# sort 默认升序排序，reverse 逆序

>>> la = [1, 2, 3, 4]
>>> lb = ['a', 'b', 'c']
>>> for e1, e2 in zip(la, lb):
...     print(e1, e2)
1 a
2 b
3 c

>>> float('-inf') < -999
True
>>> 999 < float('inf')
True
>>> float('-inf') == float('inf')
False

li = ["The Beatles", "David Bowie", "Radiohead", "Blur"]
# write
with open("1.txt", "w") as fp:
	for e in li:
		print(e)
		fp.write(e + "\n")
        
# read
with open("1.txt", "r") as fp:
    lines = fp.readlines()
for line in lines:
    print(line.split())

import os
import shutil
    
dirname = os.getcwd()
filenamelist = os.listdir(dirname)
i = 0
for name in filenamelist:
    if name[-4:] == ".jpg":
    	print(name)
        os.remove(name, str(i) + ".jpg")
        os.remove(name)
    	shutil.move(name,"./small/") 
        i += 1

python xxx.py

# A 使用 numpy
import numpy as np
li = np.random.randint(0,2,5)
# B 使用 random.sample
import random
li = [0, 1] * 10
li = random.sample(li, 3)

# 使用 random.shuffle
import random
l0 = [0] * 2
l1 = [1] * 4
li = l0 + l1
random.shuffle(li)