Python str string

The definition of strings in Python: Strings are immutable sequences of Unicode code points

Python built-in functions provide a powerful way to use strings, master common methods, and are very useful for data processing, interviews, and written examinations.

dir(str)
['__add__', '__class__', '__contains__', '__delattr__', '__dir__', '__doc__', '__eq__', '__format__', '__ge__', '__getattribute__', '__getitem__', '__getnewargs__', '__gt__', '__hash__', '__init__', '__init_subclass__', '__iter__',
'__le__', '__len__', '__lt__', '__mod__', '__mul__', '__ne__', '__new__', '__reduce__', '__reduce_ex__', '__repr__', '__rmod__', '__rmul__', '__setattr__', '__sizeof__', '__str__', '__subclasshook__', 'capitalize', 'casefold', 'cent
er', 'count', 'encode', 'endswith', 'expandtabs', 'find', 'format', 'format_map', 'index', 'isalnum', 'isalpha', 'isascii', 'isdecimal', 'isdigit', 'isidentifier', 'islower', 'isnumeric', 'isprintable', 'isspace', 'istitle', 'isuppe
r', 'join', 'ljust', 'lower', 'lstrip', 'maketrans', 'partition', 'replace', 'rfind', 'rindex', 'rjust', 'rpartition', 'rsplit', 'rstrip', 'split', 'splitlines', 'startswith', 'strip', 'swapcase', 'title', 'translate', 'upper', 'zfi
ll']

First of all, a string is a sequence, so it supports slicing and indexing operations.
Here is a summary of common built-in functions:
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s="hello testers !"
print(s.replace('hello','hi')) 
#输出:hi testers !

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s="hello testers !"
print(s.split()) #输出['hello', 'testers', '!']
print(s.partition('testers')) #输出('hello ', 'testers', ' !')

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s=" hellotesters! "
print(s.strip()) #输出hellotesters!
print(s.rstrip()) #输出 hellotesters!
print(s.lstrip()) #输出hellotesters!

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s1="hellotesters!"
s2="HELLO TESTERS!"
s3="Hello Testers!"
s4=s1="hello testers!"
print(s1.upper()) #输出HELLO TESTERS!
print(s2.lower()) #输出hello testers!
print(s3.swapcase()) #输出hELLO tESTERS!
print(s1.capitalize()) #输出Hello testers!
print(s4.title()) #输出Hello Testers!

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s1="hello testers!"
print(s1.count('l')) #输出2
print(s1.find('hello')) #输出0
print(s1.rfind('testers!')) #输出6

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s1="hellotesters!1234567890"
s2="hellotesters"
s3="1234567890"
s4="HELLOTESTERS"
print(s1.isalnum()) #输出False
print(s2.isalpha()) #输出True
print(s3.isdigit()) #输出True
print(s4.isupper()) #输出True
print(s2.islower()) #输出True

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Origin blog.csdn.net/weixin_42464956/article/details/107487280