python 字符串方法 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'