列表生成式

list(range(1,10))    # [1, 2, 3, 4, 5, 6, 7, 8, 9]

# for前面加上表达式
[x * x for x in range(1, 11)]    #[1, 4, 9, 16, 25, 36, 49, 64, 81, 100]


# for后面加if 可以用来做过滤判断，不需要加else
[x * x for x in range(1,11) if x % 2 == 0]

# 两个for循环
[m + n for m in 'abc' for n in 'cbd']  #['ac', 'ab', 'ad', 'bc', 'bb', 'bd', 'cc', 'cb', 'cd']


d = {'数学': '100', '语文': '92', '英语': '88' }
[k + '=' + v for k,v in d.items()]    # ['数学=100', '语文=92', '英语=88']


# for 前面是是表达式，用if语句需要加上else
[x if x % 2 ==0 else -x for x in range(1,11)] # [-1, 2, -3, 4, -5, 6, -7, 8, -9, 10]