python3字符串操作总结

>>>s = 'hello'>>>s[0:3]'he' >>>s[:] #截取全部字符'hello' 

s.strip() #消除字符串s左右两边的空白字符（包括'/t'，'/n','/r',''） s.strip('0') #消除字符串s左右两边的特殊字符（如'0'）,字符串中间的'0'不会删除

>>>s = '000hello00world000'>>>s.strip('0')'hello00world's.strip('12')等价于s.strip('21')

>>>s = '12hello21'>>>s.strip('12')'hello'

s1 = 'hello's2 = s1 # s2 = 'hello'

s1 = 'hello's2 = s1[0:2] #s2 = 'he'

s1 = 'hello's2 = 'world's3 = s1 + s2 #s3 = 'helloworld'

import operators3 = operator.concat(s1,s2) #concat为字符串拼接函数

>>>import operator>>>operator.eq('abc','edf') #根据ASCII码比较Flase>>>operator.gt('abc','ab')True

>>>s1 = 'abc'>>>s2 = 'ab'>>>s1 > s2True>>>s1 == s2False

>>>s1 = 'hello'>>>len(s1)5

>>>s1 = 'hello'>>>max(s1) #求字符串s1中最大字符'o'>>>min(s1) #求字符串s2中最小字符'e'

>>>s1 = 'hello'>>>s2 = 'WORLD'>>>s3 = 'hello world'>>>s1.upper() 'HELLO'>>>s2.lower() 'world'>>>s3.title() 'Hello World'>>>s3.capitalize() 'Hello world'>>>s3.title().swapcase() 'hELLO wORLD'

>>>s1 = 'hello'>>>s1[::-1]'olleh'

>>>s1 = 'hello,world'>>>s1.split(',')['hello','world']

>>>l = ['hello','world']>>>str = '-'>>>str.join(l)'hello-world'

>>>s1 = 'today is a fine day'>>>s1.find('is')6>>>s1.find('is',3)6>>>s1.find('is',7,10)-1

str.replace(old,new[,max]) #old为旧串，new为新串，max可选，为替换次数

>>>s1 = 'today is a find day'>>>s1.replace('find','rainy')'today is a rainy day'

>>>s1 = 'hello'>>>s1.islower()True>>>s1.isdigit()False

a = 'My name is Jason'#使用split(str="", num=string.count(str)) 方法根据不同的分割符转，也可指定分割次数，可使用 ' '.join方法转回>>> 'My name is Jason'.split(' ')['My', 'name', 'is', 'Jason']>>> ' '.join(['My', 'name', 'is', 'Jason'])'My name is Jason'

>>> 'cat.jpg'.startswith('cat')True>>> 'cat.jpg'.startswith('cat',0,3)True>>> 'cat.jpg'.endswith('.jpg')True>>> 'cat.jpg'.endswith('.jpg',-4)True

>>> s = ' Hello World  '>>> s.strip()'Hello World'>>> s.lstrip()'Hello World  '>>> s.rstrip()' Hello World'#扩展>>> 'www.example.com'.lstrip('www.')'example.com'>>> 'www.example.com'.lstrip('cmowz.')'example.com'

#字符串的格式化>>> '{name},{sex},{age}'.format(age=15,sex='male',name='小安')'小安,male,15'>>> '{1},{0},{2}'.format('15','小安','male')'小安,15,male'>>> '{},{},{}'.format('小安', '15','male')'小安,15,male'#如果字符串中的所有字符都是数字，并且至少有一个字符，则返回真，否则返回假>>> '123'.isdigit()True>>> '123一二三'.isdigit()False#isnumeric 是所有字符都是数字字符返回真>>> '123一二三'.isnumeric()True#字符串是否大小写判断>>> 'abc'.islower()True>>> 'Abc'.islower()False>>> 'ABC'.isupper()True#首字母大写>>> "they're bill's friends from the UK".title()"They'Re Bill'S Friends From The Uk"#正则处理方式>>> import re>>> def titlecase(s):...   return re.sub(r"[A-Za-z]+('[A-Za-z]+)?",...          lambda mo: mo.group(0)[0].upper() +...               mo.group(0)[1:].lower(),...          s)...>>> titlecase("they're bill's friends.")"They're Bill's Friends."#返回指定长度字符串，前面补0，一般存csv文件中含00开头的字符0会被抹掉>>> code = '1'>>> code.zfill(6)'000001'#字符串长度及遍历>>> s = '混蛋哥'>>> len(s)3>>> for i in s:  print(i)混蛋哥>>>