python字符串常用方法

 In [1]: str1='jiangwei520' In [2]: str2='jiang wei' In [3]: str3='520' In [4]: str4='520 1314' In [5]: str1.isalnum() Out[5]: True In [6]: str2.isalnum() Out[6]: False In [7]: str3.isalnum() Out[7]: True In [8]: str4.isalnum() Out[8]: False

 In [11]: s1='j w' In [12]: s2='jw' In [13]: s1.isalpha() Out[13]: False In [14]: s2.isalpha() Out[14]: True

 In [15]: n1='12 34' In [16]: n2='1234' In [17]: n3='1.1' In [18]: n1.isdigit() Out[18]: False In [19]: n2.isdigit() Out[19]: True In [20]: n3.isdigit() Out[20]: False

 In [23]: s1='j w' In [24]: s2='jw' In [25]: s3='JW' In [26]: s1.islower() Out[26]: True In [27]: s2.islower() Out[27]: True In [28]: s3.islower() Out[28]: False

 In [29]: s1='J w' In [30]: s2="J W" In [31]: s3="JＷ" In [32]: s4='Jw' In [33]: s1.isupper() Out[33]: False In [34]: s2.isupper() Out[34]: True In [35]: s3.isupper() Out[35]: True In [36]: s4.isupper() Out[36]: False

 In [37]: s1='hello world' In [38]: s2='Hello World' In [39]: s3='Hello,world' In [40]: s4='HELLO WORLD' In [41]: s1.istitle() Out[41]: False In [42]: s2.istitle() Out[42]: True In [43]: s3.istitle() Out[43]: False In [44]: s4.istitle() Out[44]: False

 In [47]: s4 Out[47]: 'HELLO WORLD' In [48]: s4.lower() Out[48]: 'hello world' In [49]: s2 Out[49]: 'Hello World' In [50]: s2.lower() Out[50]: 'hello world'

 In [54]: s1 Out[54]: 'HEllo WOrld' In [55]: s3 Out[55]: 'Hello,world' In [56]: s1.upper() Out[56]: 'HELLO WORLD' In [57]: s3.upper() Out[57]: 'HELLO,WORLD'

 lstrip()和 rstrip() 类似 In [61]: s1='  hello     world   !!!  ' In [62]: s1.strip() Out[62]: 'hello     world   !!!' In [63]: s2='**** jw---love---you ****' In [64]: s2.strip('*') Out[64]: ' jw---love---you ' #应该是去除两边的 　In [107]: a='***111***' In [108]: a.lstrip('*') Out[108]: '111***' In [109]: a.rstrip('*') Out[109]: '***111' In [110]: a.strip('*') Out[110]: '111'

 In [72]: a='小喵和小九' In [73]: a.replace('喵','喵喵').replace('九','九九') Out[73]: '小喵喵和小九九' In [74]: b='jiangwei is a good good good boy' In [75]: b.replace('good','nice') Out[75]: 'jiangwei is a nice nice nice boy' In [76]: b.replace('good','nice',2) Out[76]: 'jiangwei is a nice nice good boy' In [77]: b.replace('good','nice',1) Out[77]: 'jiangwei is a nice good good boy'

 In [92]: path1 Out[92]: 'a/b/c/d' In [93]: path1.split('/') Out[93]: ['a', 'b', 'c', 'd'] In [88]: path='/home/centos/python3.6' In [89]: path Out[89]: '/home/centos/python3.6' In [90]: path.split('/') Out[90]: ['', 'home', 'centos', 'python3.6']

 endswith():类似 In [94]: a='helloworld' In [95]: b='hello world' In [96]: a.startswith('hello') Out[96]: True In [97]: b.startswith('hello') Out[97]: True In [98]: b.startswith('he') Out[98]: True

 In [111]: print('{name}---->{age}'.format(name='xjm',age=21)) xjm---->21 In [112]:

 In [112]: s='hello world python ' In [113]: s.title() Out[113]: 'Hello World Python ' #与capitalize不同。就第一个单词的首字母大写 　In [128]: a='hello world python' In [129]: a.capitalize() Out[129]: 'Hello world python'

 In [117]: a='.' In [118]: a.join('jwlove') Out[118]: 'j.w.l.o.v.e' 　In [124]: a='/' In [125]: b=('user','local') In [127]: a.join(b) Out[127]: 'user/local'

 In [137]: a='Linux' In [138]: a.center(25,'*') Out[138]: '**********Linux**********' In [140]: a.center(25) Out[140]: '     Linux    ' #ljust和rjust类似 　In [142]: a.ljust(10,'-') 　Out[142]: 'Linux-----' 　In [143]: a.rjust(10,'-') 　Out[143]: '-----Linux'

 In [151]: a='如果\n没有\r如果' In [154]: print(a) 如果 如果 In [157]: a.splitlines() Out[157]: ['如果', '没有', '如果']

 In [158]: a='hello world {course}' In [160]: course1='python' In [161]: course2='java' In [178]: a.format(course=course1) Out[178]: 'hello world java' In [179]: a.format(course=course2) Out[179]: 'hello world python' In [181]: a.format_map(vars()) Out[181]: 'hello world python'