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‘

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‘]

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‘