Python Str内部功能-个人课堂笔记，课后总结

Posted 2020-10-13

查看str内部功能，可通过和int一样的方法，或者使用type(str)、dir(str)来查看。

1、capitalize：首字母大写

　　S.capitalize() -> string

str1 = "parr"
result = str1.capitalize()
print(result)

#返回Parr

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2、center(self, width, fillchar=None)：内容居中，width：总长度；fillchar：空白处填充内容（默认无）

　　S.center(width[, fillchar]) -> string

str1 = "parr"
result = str1.center(10,"*")
print(result)

#返回***parr***

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3、count(self, sub, start=None, end=None)：str的子序列个数，区分大小写

　　S.count(sub[, start[, end]]) -> int

str1 = "parrAbcadb"
result = str1.count("a")
print(result)

#返回2，表示找到两个a

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4、decode(self, encoding=None, errors=None)：解码

　　S.decode([encoding[,errors]]) -> object

str1 = "哈哈"
result = str1.encode()
str2 = result.decode()
print(str2)

屏幕打印：哈哈

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5、encode(self, encoding=None, errors=None)：编码

　　S.encode([encoding[,errors]]) -> object

str1 = "哈哈"
result = str1.encode()
print(result)

#返回b‘\xe5\x93\x88\xe5\x93\x88‘

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6、endswith(self, suffix, start=None, end=None)：受否以XX结束，返回bool型的值

　　S.endswith(suffix[, start[, end]]) -> bool

str1 = "parr Luck 2017"
result = str1.endswith("2017")
print(result)

#屏幕打印Ture

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7、expandtabs(self, tabsize=None)：将Tab转换为空格，默认一个Tab八个空格

　　S.expandtabs([tabsize]) -> string

str1 = "parr\thello"
result = str1.expandtabs()
print(result)

屏幕打印：parr    hello

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8、find(self, sub, start=None, end=None)：寻找子序列位置，如没找到返回-1

　　S.find(sub [,start [,end]]) -> int

str1 = "parr"
result = str1.find(‘a‘)
print(result)

#屏幕打印1，表示a在1位置

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9、isalnum(self)：是否是字母或数字，返回bool型的值

　　S.isalnum() -> bool

str1 = "parr2017"
result = str1.isalnum()
print(result)

#屏幕打印：Ture

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10、isalpha(self): ：是否是字母

　　S.isalpha() -> bool

str1 = "parr"
result = str1.isalpha()
print(result)

#屏幕打印：Ture

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11、isnumeric(self)：是否是数字

　　S.isnumeric() -> bool

str1 = "2017"
result = str1.isnumeric()
print(result)

#屏幕打印Ture

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12、islower(self)：是否是小写

　　isupper(self):：是否是大写

　　S.islower() -> bool

str1 = "parr"
result = str1.islower()
print(result)

#返回Ture

str1 = "parr"
result = str1.isupper()
print(result)

#返回False

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13、replace(self, old, new, count=None)：替换内容

　　S.replace(old, new[, count]) -> string

str1 = "parr"
result = str1.replace(‘a‘,‘hello‘)
print(result)

#屏幕打印：phellorr

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14、split(self, sep=None, maxsplit=None)：分割内容，maxsplit最多分割几次，返回一个列表

　　S.split([sep [,maxsplit]]) -> list of strings

str1 = "parr"
result = str1.split(‘a‘)
print(result)

#返回[‘p‘, ‘rr‘]

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15、splitlines(self, keepends=False):：根据换行分割，返回一个列表

　　S.splitlines(keepends=False) -> list of strings

str1 = """parr
        hello
        everyone
"""
result = str1.splitlines()
print(result)

#返回[‘parr‘, ‘        hello‘, ‘        everyone‘]

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16、startswith(self, prefix, start=None, end=None)：是否起始为prefix中的内容

　　S.startswith(prefix[, start[, end]]) -> bool

str1 = """parr
        hello
        everyone
"""
result = str1.startswith(‘parr‘)
print(result)

#返回Ture

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17、strip(self, chars=None)：移除两端空白

　　S.strip([chars]) -> string or unicode

str1 = "            parr2017              "
result = str1.strip()
print(result)

#返回parr2017

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18、__contains__(self, y)：检查y是否包含于x中

　　x.__contains__(y) <==> y in x

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