字符串的操作方法:
Python的数据类型字符串、布尔类型、列表、元组、字典等等,今天就简单介绍一下字符串的操作方法。
Python的学习就是要多练习,好记性不如烂笔头,我们在实际中看看吧。
下面就列举一些例子供大家参考:
字符串的定义必须使用单引号或者双引号,这两个没有什么区别。
name = 'winter' #定义一个字符串
print(type(name)) #查看南数据类型,type是内置的一个方法可以查看数据类型
print(name) #打印出字符串
运行结果:
<class 'str'>
winter
下面来查看一下字符串内置的一些方法(下面仅列举一些常用的方法)
def __contains__(self, *args, **kwargs): # real signature unknown
""" Return key in self. """
查看字符是否在字符串中
name = 'winter' #定义一个字符串
result = name.__contains__('w') #判断字符是否在字符串中,返回值为布尔值
result1 = name.__contains__('s')
print(result)
print(result1)
True w在字符串winter中,因此返回True
False s不在字符串winter中,因此返回False
contains和in一样都是判断字符是否在字符串中
name = 'winter'
result = 'w' in name
print(result)
True
def __eq__(self, *args, **kwargs): # real signature unknown
""" Return self==value. """
判断字符串的只是否相等
name = 'winter'
result = name.__eq__('winter')
result1 = name.__eq__('thunder')
print(result)
print(result1)
True
False
def capitalize(self): # real signature unknown; restored from __doc__
"""
B.capitalize() -> copy of B
Return a copy of B with only its first character capitalized (ASCII)
and the rest lower-cased.
首字母变大写
name = 'winter'
result = name.capitalize()
print(result)
print(name)
Winter
winter
def center(self, width, fillchar=None): # real signature unknown; restored from __doc__
"""
B.center(width[, fillchar]) -> copy of B
Return B centered in a string of length width. Padding is
done using the specified fill character (default is a space).
""" 返回B以一长串宽度为中心。 填充是使用指定的填充字符(默认为空格)
name = 'winter' #定义一个字符串
result = name.center(20) #打印20个字符串,以winter为中心
print(len(result)) #打印result的字符串长度
print(result) 打印result的值,字符串长度不够,默认使用空格填充
result1 = name.center(20,'*') #打印20个字符串,字符串长度不够,默认使用*填充
result2 = name.center(20,'-') #打印20个字符串,字符串长度不够,默认使用-填充
print(result1)
print(result2)
20
winter
*******winter*******
-------winter-------
def count(self, sub, start=None, end=None): # real signature unknown; restored from __doc__
"""
B.count(sub[, start[, end]]) -> int
Return the number of non-overlapping occurrences of subsection sub in
bytes B[start:end]. Optional arguments start and end are interpreted
as in slice notation.
""" 统计字符出现的次数,加参数可以统计某个范围内的次数
name = 'welcometolearnpython'
result = name.count('l') #统计字符l出现的次数
result1 = name.count('l',0,9) #统计前八个字符中l出现的次数,包括前面的数字不包括后面的
print(result)
print(result1)
2
1
def endswith(self, suffix, start=None, end=None): # real signature unknown; restored from __doc__
"""
B.endswith(suffix[, start[, end]]) -> bool
Return True if B ends with the specified suffix, False otherwise.
With optional start, test B beginning at that position.
With optional end, stop comparing B at that position.
suffix can also be a tuple of bytes to try.
""" 判断字符串是否以某个字符结尾
name = 'winter'
result = name.endswith('r') #判断字符串是否以r结尾
result1 = name.endswith('s') #判断字符串是否以s结尾
result2 = name.endswith('t',0,4) #判断前四个字符是否以t结尾
print(result)
print(result1)
print(result2)
True
False
True
def find(self, sub, start=None, end=None): # real signature unknown; restored from __doc__
"""
B.find(sub[, start[, end]]) -> int
Return the lowest index in B where subsection sub is found,
such that sub is contained within B[start,end]. Optional
arguments start and end are interpreted as in slice notation.
Return -1 on failure. #判断字符出现在字符串中的位置
name = 'winterorthunder'
result = name.find('n') #判断字符n出现的位置,但是只标注第一次出现过的位置,当字符不存在的时候返回-1
result1 = name.find('s')
print(result)
print(result1)
print(name)
2
-1
def __format__(self): # real signature unknown; restored from __doc__
"""
complex.__format__() -> str
Convert to a string according to format_spec.
""" #转换字符串
name = 'name:{0} age:{1}'
result = name.format('winter','25')
name1 = 'Name:{name} Age:{age}'
result1 = name1.format(name = 'winter',age = '25')
print(result)
print(result1)
name:winter
age:25
Name:winter
Age:25
def partition(self, sep): # real signature unknown; restored from __doc__
"""
S.partition(sep) -> (head, sep, tail)
Search for the separator sep in S, and return the part before it,
the separator itself, and the part after it. If the separator is not
found, return S and two empty strings.
""" #字符串分割
name = 'winterlovethunder'
result = name.partition('love') #以love把字符串分隔
print(result)
('winter', 'love', 'thunder')
def replace(self, old, new, count=None): # real signature unknown; restored from __doc__
"""
S.replace(old, new[, count]) -> str
Return a copy of S with all occurrences of substring
old replaced by new. If the optional argument count is
given, only the first count occurrences are replaced.
""" #字符串替换
name = 'winterwinterwinter'
result = name.replace('w','h') #把字符串中的w替换成h
result2 = name.replace('w','h',2) #把字符串中的w替换成h,只替换两次
print(result)
print(result2)
print(name)
hinterhinterhinter
hinterhinterwinter
winterwinterwinter
ljust方法是返回字符串左对齐的字符串宽度,填充是通过指定的fillchar(默认是空格),如果宽度小于字符串长度返回原始字符串
ljust语法:str.ljust(width[, fillchar])
参数:
1,width---填充后字符串的总长度
2,fillchar ---填充字符,默认是空格
例子:
name = 'winter'
result = name.ljust(20)
result1 = name.ljust(20,'!') #输出的总长度为20,不够的话使用!填充
print(len(name)) #输出原来字符串的长度
print(len(result)) #输出填充后的字符串长度
print(result) #输出没有指定填充符的字符串,默认是空格
print(result1) #输出没有指定填充符的字符串
6
20
winter
winter!!!!!!!!!!!!!!
rjust方法是返回原字符串右对齐,并使用空格填充至长度的新字符串。填充是通过指定的fillchar(默认是空格),如果宽度小于字符串长度返回原始字符串
rjust语法:str.rjust(width[, fillchar])
参数:
1,width---填充后字符串的总长度
2,fillchar ---填充字符,默认是空格
例子:
name = 'winter'
result = name.rjust(20)
result1 = name.rjust(20,'!') #输出的总长度为20,不够的话使用!填充
print(len(name)) #输出原来字符串的长度
print(len(result)) #输出填充后的字符串长度
print(result) #输出没有指定填充符的字符串,默认是空格
print(result1) #输出没有指定填充符的字符串
6
20
winter
!!!!!!!!!!!!!!winter
在此就不一一列举了,有问题的朋友可以联系我,页欢迎大家向我提出意见,谢谢大家。
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