字符串的详细玩法

原生格式

>>> name = "abcdef"
>>> name = "abc\tdef\n" #加入制表符和换行符
>>> 
>>> name
'abc\tdef\n'
>>> print(name) #效果
abc	def

>>> name = r"abc\tdef\n" #r输出原生格式
>>> print(name)
abc\tdef\n

首字母大写

>>> name.capitalize()
'Abc\\tdef\\n'

大写变小写

>>> "ABcde".casefold()
'abcde'

指定字符长度及填充

>>> name.center(50,'-') #50长度，‘-1‘填充
'--------------------abc\\tdef\\n--------------------'

切片中取出现字符次数

>>> name.count("a",0,-1) #a取字符，从0开始，到-1结束
1

判断以什么结尾

>>> name
'abc\\tdef\\n'
>>> name.endswith("n") 
True

找字符

>>> name = "abdcdessf"
>>> name.find("f")
8

>>> name.find("f",2) #从2开始找
8

>>> name.find("g",2) #找不到返回-1
-1

占位符

>>> a = "welcome {0} to login in,dear {1} user :)"
>>> a.format("john",3)
'welcome john to login in,dear 3 user :)'

>>> a = "welcome {name} to login in,dear {number} user :)"
>>> a.format(name = "jack", number = 5)
'welcome jack to login in,dear 5 user :)'

索引

>>> a
'welcome {name} to login in,dear {number} user :)'
>>> a.index(")")
47

整数

>>> '5'.isdigit()
True

小写

>>> "AAess".lower()
'aaess'

空格

>>> ''.isspace()
False
>>> '  '.isspace()
True

大写

>>> "AAAef".isupper()
False
>>> "AAAEF".isupper()
True
>>> "AAAe".upper()
'AAAE'

拼接

>>> name = ["aa","bb","cc"]
>>> 
>>> 
>>> "".join(name)
'aabbcc'
>>> " ".join(name)
'aa bb cc'
>>> "-".join(name)
'aa-bb-cc'

保留左边填充

>>> name.ljust(50,'*') #50个字符，以*填充
'aa-bb-cc******************************************'

保留右边填充

>>> name.rjust(50,'*')
'******************************************aa-bb-cc'

去掉两边的空格和换行符

>>> a = ' shjh  '
>>> a
' shjh  '
>>> a = '\t shjh  \n'
>>> a
'\t shjh  \n'
>>> print(a)
	 shjh  

>>> a.strip()
'shjh'
>>> a = '\t sh\tjh  \n'
>>> 
>>> print(a)
	 sh	jh  

>>> a.strip()
'sh\tjh'

去掉左边的

>>> a = '\t sh\tjh  \n'
>>> a.lstrip()
'sh\tjh  \n'

去掉右边的

>>> a.rstrip()
'\t sh\tjh'

替换

>>> a = "today is rainny, not good"
>>> a.replace("rainny","sunny")
'today is sunny, not good'

列表—字符串

>>> a = ["1","2","3"]
>>> ",".join(a)
'1,2,3'
>>> a1=",".join(a)
>>> a1
'1,2,3'

字符串变列表

>>> a1
'1,2,3'
>>> a1.split()
['1,2,3']
>>> a1.split(",")
['1', '2', '3']

以空格分割

'1,2,3  456'
>>> a1.split(" ")
['1,2,3', '', '456']

大小写互换

>>> a="AAAAeeee"
>>> a.swapcase()
'aaaaEEEE'

长度以0补

'aaaaEEEE'
>>> a.zfill(30)
'0000000000000000000000AAAAeeee'