字符串方法
1.center居中字符串,根据width两侧填充
>>>'apple'.center(8)
'_apple__'
2.find查找字符串,返回索引(lfind\rfind 从首查\从尾查)
>>>'apple banana orange'.find('banana')
6
3.join合并序列
>>>a=['1','2','3','4']
>>>b='+'
>>>b.join(a)
1+2+3+4
4.split拆分序列
>>>'1+2+3+4'.split('+')
['1','2','3','4']
5.strip删除首尾指定字符,默认空格(lstrip\rstrip 删首\删尾)
>>>'*** SSS * TTT * RRR!!! ***'.strip(' *!'
'SSS * TTT * RRR'
6.replace\translate替换字符串(后者只能单个替换,需要做映射)
>>> 'this is an apple!'.replace('apple','banana')
'this is an banana!'
>>>table=str.maketrans('ae')
>>>'this is an apple!'.translate(table)
'this is en epple!'