1、加,乘
>>> 'hello'+'world' 'helloworld' >>> 'hello'*3 'hellohellohello'
2、字符串运算(一)
>>> 'hello world'[0]
'h'
>>> 'hello world'[4]
'o'
>>> 'hello world'[-1] [-n]是指从末尾字符开始往前数第n个字符
'd'
>>> 'hello world'[-3]
'r'
3、字符串运算(二)
>>> 'hello world'[0:3] [0:3]截取第0位到第2位字符 'hel' >>> 'hello world'[0:-1] -1是步长的概念 'hello worl' >>> 'hello world'[0:-3] 'hello wo'
4、字符串运算(三)
>>> 'hello world'[6:11] 'world' >>> 'hello world'[6:20] 'world' >>> 'hello world'[6:] 'world' >>> 'hello world'[-5:] 'world'