1、 isalnum() :判断字符串所有的字符都是字母或者数字。返回true和false
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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
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2、 isalpha() :判断字符串所有的字符都是字母。返回true和false
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In [ 11 ]: s1 = 'j w'
In [ 12 ]: s2 = 'jw'
In [ 13 ]: s1.isalpha()
Out[ 13 ]: False
In [ 14 ]: s2.isalpha()
Out[ 14 ]: True
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3、 isdigit(): 判断字符串所有的字符都是数字。返回true和false
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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
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4、 islower() :判断所有的字符都是小写。
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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
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5、 isupper() :判断所有的字符都是大写。
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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
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6、 istitle() :判断每个单词的首字母都是大写。
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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
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7、 lower() :转小写
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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'
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7、 upper() :转大写
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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'
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8、 strip([chars]) :去除
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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'
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9、 replace(old ,new, [count]) :替换
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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'
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10、 split() :切割。返回列表。
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In [ 92 ]: path1
Out[ 92 ]: 'a/b/c/d'
In [ 93 ]: path1.split( '/' )
Out[ 93 ]: [ 'a' , 'b' , 'c' , 'd' ]
In [ 89 ]: path
Out[ 89 ]: '/home/centos/python3.6'
In [ 90 ]: path.split( '/' )
Out[ 90 ]: [' ', ' home ', ' centos ', ' python3. 6 ']
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11、 startswith() :以指定的字符串开头。发货true和false。
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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
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12、 format() :格式化输出
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In [ 111 ]: print ( '{name}---->{age}' . format (name = 'xjm' ,age = 21 ))
xjm - - - - > 21
In [ 112 ]:
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13、 title() : 把每个字符串的首字母大写
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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'
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14、 join() :插入
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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'
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15、 center(width,char) :扩充
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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'
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16、 splitlines(): 根据\r \n \r\n 切割。返回列表
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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' ]
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17、 format_map() :格式化输出
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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'
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总结
以上所述是小编给大家介绍的python字符串常用方法,希望对大家有所帮助,如果大家有任何疑问请给我留言,小编会及时回复大家的。在此也非常感谢大家对服务器之家网站的支持!
原文链接:http://www.cnblogs.com/xjmlove/p/9179227.html