1，大小写翻转
>>> str=‘hello,GhostWU‘ >>> str.swapcase() ‘HELLO,gHOSTwu‘
2，从一串字符串中，提取纯数字组合
>>> str="adfask22jkljhh3jkljhgh435" >>> ‘‘.join( [s for s in str if s.isdigit() ] ) ‘223435‘ >>>
等价于：
>>> str="adfask22jkljhh3jkljhgh435" >>> l = [] >>> for s in str: ... if s.isdigit(): ... l.append( s ) ... >>> l [‘2‘, ‘2‘, ‘3‘, ‘4‘, ‘3‘, ‘5‘] >>> ‘‘.join( l ) ‘223435‘ >>>
3，统计字符的出现次数，以字符为键，大小写视为相同字符
>>> s = "abcsABCDEFabcAbcdFEA" >>> s = s.lower() >>> s ‘abcsabcdefabcabcdfea‘ >>> res = dict( [ ( key, s.count( key ) ) for key in set( s ) ] ) >>> res {‘a‘: 5, ‘c‘: 4, ‘b‘: 4, ‘e‘: 2, ‘d‘: 2, ‘f‘: 2, ‘s‘: 1} >>>
4，字符串去重，按原来的顺序输出
>>> s ‘abcccabdefdx‘ >>> l = list( s ) >>> set_list = list( set( l ) ) >>> res = set_list.sort( key=l.index ) >>> res >>> set_list [‘a‘, ‘b‘, ‘c‘, ‘d‘, ‘e‘, ‘f‘, ‘x‘] >>>
5，字符串反转
>>> s = ‘abc‘ >>> s[::-1] ‘cba‘
6，去除字符串中的数字，然后排序，如果出现相同的字母，如aA，大写字母排在小写字母的前面
#!/usr/bin/python #coding:utf-8 s = ‘abcDBA233ABC1‘ l = sorted( s ) upper_list = [] lower_list = [] for v in l: if v.isupper(): upper_list.append( v ) elif v.islower(): lower_list.append( v ) else: pass #print upper_list, lower_list for x in upper_list: x_lower = x.lower() if x_lower in lower_list: lower_list.insert( lower_list.index( x_lower ), x ) print ‘‘.join( lower_list )
