python字符串操作，, 1 #首字母大写

python字符串操作，, 1 #首字母大写

  1 #首字母大写  2 str = "my name is zhangsan"  3 print(str.capitalize())  4 >>My name is zhangsan  5   6 #统计字符串里有几个字符  7 str = ‘my name is zhangsan‘  8 print(str.count(‘i‘)) #print(str.count(‘a‘,5,18))  9 >>1 10  11 #居中，不足按参数形式补全 12 str = ‘my name is zhangsan‘ 13 print(str.center(50,‘-‘)) 14 >>---------------my name is zhangsan---------------- 15  16 #左对齐，右边不足按参数形式补全 17 str = "my name is zhangsan, and age is 22" 18 print (str.ljust(50,‘-‘)) 19 >>my name is zhangsan, and age is 22---------------- 20  21 #右对齐，左边不足按参数形式补全 22 str = "my name is zhangsan, and age is 22" 23 print (str.rjust(50,‘-‘)) 24 >>----------------my name is zhangsan, and age is 22 25  26 #制表符转换为空格，参数为空格数量 27 str = ‘my name is zh\tangsan‘ 28 print(str) 29 print(str.expandtabs(10)) 30  31 #判断是否为相应字符结尾 32 str = ‘my name is zhangsan‘ 33 print(str.endswith(‘san‘)) 34  35 #string转换为bytes 36 str = ‘我爱中国‘ 37 print(str.encode()) 38 >>b‘\xe6\x88\x91\xe7\x88\xb1\xe4\xb8\xad\xe5\x9b\xbd‘ 39  40 #bytes转换为string 41 bs = b‘\xe6\x88\x91\xe7\x88\xb1\xe4\xb8\xad\xe5\x9b\xbd‘ 42 print(bs.decode()) 43 >>我爱中国 44  45 #在规定位置查找字符，找到返回index，找不到-1 46 str = ‘my name is zhangsan‘ 47 print(str.find(‘a‘,3,10)) 48  49 #格式化字符串 50 str = ‘my {} is {}‘ 51 print(str.format(‘name‘,‘zhangsan‘)) 52 >>my name is zhangsan 53 #可以不按顺序 54 str = ‘my {1} is {0}‘ 55 print(str.format(‘name‘,‘zhangsan‘)) 56 >>my zhangsan is name 57 #也可以这样 58 str = ‘my {a} is {b}‘ 59 print(str.format(b=‘name‘,a=‘zhangsan!!!‘)) 60 >>my zhangsan!!! is name 61  62 #用map方式格式化 63 str = "my name is {name}, and age is {age}" 64 print(str.format_map({‘name‘:‘zhangsan‘,‘age‘:‘22‘})) 65 >>my name is zhangsan, and age is 22 66  67 #判断是否全大写 68 str = ‘AAA‘ 69 print(str.isupper()) 70 >>True 71  72 #判断首字母大写 73 str = ‘Aa‘ 74 print(str.istitle()) 75 >>True 76  77 #判断是不是空格 78 str = ‘ ‘ 79 print(str.isspace()) 80 >>True 81  82 #判断是不是由数字字符组成的字符串 83 str = ‘111‘ 84 print(str.isnumeric()) 85 >>True 86  87 #判断是否全字母组成 88 str = ‘aaaa‘ 89 print(str.isalpha()) 90 >>True 91  92 #检测指定str是否存在与原str中，可以指定开始结束，与find()区别在于，如果没查到会报异常 93 str = "my name is zhangsan, and age is 22" 94 print(str.index(‘a‘)) 95 >>4 96 print(str.index(‘x‘)) 97 >>ValueError: substring not found 98  99 #判断是否小写字母组成100 str = ‘aaa‘101 print(str.islower())102 >>True103 104 #判断是否字母和数字组成105 str = ‘a12Aaa‘106 print(str.isalnum())107 >>True108 109 #判断是否只由数字构成110 str = ‘111‘111 print(str.isdigit())112 >>True113 114 #用于将序列中的元素以指定的字符连接生成一个新的字符串115 str = "-";116 seq = ("a", "b", "c"); # 字符串序列117 print str.join( seq );118 >>a-b-c119 120 #转换字符串中所有大写字符为小写。121 str = "my nAme is zhANGSAN, and age is 22"122 print (str.lower())123 >>my name is zhangsan, and age is 22124 125 #移除字符串头尾指定的字符（默认为空格）126 str = "*****this is string example....wow!!!*****"127 print (str.strip( ‘*‘ ))128 >>this is string example....wow!!!129 130 #截掉字符串左边的空格或指定字符，默认为空格131 str = "1111my name is zhangsan, and age is 221111"132 print (str.lstrip(‘1‘))133 >>my name is zhangsan, and age is 221111134 135 #截掉字符串右边的空格或指定字符，默认为空格136 str = "1111my name is zhangsan, and age is 221111"137 print (str.rstrip(‘1‘))138 >>1111my name is zhangsan, and age is 22139 140 #intab替换为outtab，一一对应，转换为ask码格式，translate()把ask码转换为对于字符141 intab = "aeiou"142 outtab = "12345"143 trantab = str.maketrans(intab, outtab)144 print(trantab)145 str = "this is string example....wow!!!"146 print (str.translate(trantab))147 >>{97: 49, 101: 50, 105: 51, 111: 52, 117: 53}148 >>th3s 3s str3ng 2x1mpl2....w4w!!!149 150 #返回一个3元的元组，第一个为分隔符左边的子串，第二个为分隔符本身，第三个为分隔符右边的子串。151 str = "http://www.w3cschool.cc/"152 print(str.partition(‘//‘))153 >>(‘http:‘, ‘//‘, ‘www.w3cschool.cc/‘)154 155 #返回子字符串 str 在字符串中最后出现的位置，如果没有匹配的字符串会报异常，你可以指定可选参数[beg:end]设置查找的区间156 str = "1111my name is zhangsan, and age is 221111"157 print (str.rindex(‘isx‘))158 >>ValueError: substring not found159 160 #返回字符串最后一次出现的位置，如果没有匹配项则返回-1161 str = "1111my name is zhangsan, and age is 221111"162 print (str.rfind(‘isx‘))163 >>-1164 165 #方法把字符串中的 old（旧字符串） 替换成 new(新字符串)，如果指定第三个参数max，则替换不超过 max 次166 str = "this is string example....wow!!! this is really string"167 print (str.replace("is", "was"))168 print (str.replace("is", "was", 3))169 >>thwas was string example....wow!!! thwas was really string170 >>thwas was string example....wow!!! thwas is really string171 172 #把字符串切割成列表，默认空格为切割符173 str = "       1111my name is zhangsan, and age is 221111   "174 print (str.split())175 >>[‘1111my‘, ‘name‘, ‘is‘, ‘zhangsan,‘, ‘and‘, ‘age‘, ‘is‘, ‘221111‘]176 177 #按照行(‘\r‘, ‘\r\n‘, \n‘)分隔，返回一个包含各行作为元素的列表，如果参数 keepends 为 False，不包含换行符，如果为 True，则保留换行符。178 str1 = ‘ab c\n\nde fg\rkl\r\n‘179 print(str1.splitlines())180 str2 = ‘ab c\n\nde fg\rkl\r\n‘181 print(str2.splitlines(True))182 183 #用于检查字符串是否是以指定子字符串开头，如果是则返回 True，否则返回 False。如果参数 beg 和 end 指定值，则在指定范围内检查。184 str = "this is string example....wow!!!"185 print (str.startswith( ‘this‘ ))186 print (str.startswith( ‘string‘, 8 ))187 print (str.startswith( ‘this‘, 2, 4 ))188 >>True189 >>True190 >>False191 192 #转换成大写193 str = "this is string example....wow!!!"194 print (str.swapcase())195 >>THIS IS STRING EXAMPLE....WOW!!!196 197 #将字符串中的小写字母转为大写字母。198 str = "this is string example....wow!!!"199 print (str.upper())200 >>THIS IS STRING EXAMPLE....WOW!!!201 202 #首字母大写203 str = "this is string example....wow!!!"204 print (str.title())205 >>This Is String Example....Wow!!!206 207 #左边补零208 str = "123456789"209 print (str.zfill(9))210 print (str.zfill(10))211 print (str.zfill(11))212 >>123456789213 >>0123456789214 >>00123456789

python字符串操作