【马士兵】 Python基础--11

Python基础–11

字符串的驻留机制

a='Python'
b='Python'
c='Python'
print('a：',a,id(a))
print('b：',b,id(b))
print('c：',c,id(c))
# a： Python 2834106576176
# b： Python 2834106576176
# c： Python 2834106576176
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字符串查找

字符串查询操作方法

s='hello,hello'
print(s.index('lo'))#3
print(s.rindex('lo'))#9
print(s.find('lo'))#3
print(s.rfind('lo'))#9
 
#print(s.index('k'))ValueError: substring not found
print(s.find('k')) #-1
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字符串大小写转换

字符串的大小写转换方法

转换之后，会产生一个新的字符串对象

s='hello,python'
print(s,id(s))
print(s.upper(),id(s.upper()))
# hello,python 2564162926064
# HELLO,PYTHON 2564162925936
a='HELLO,PYTHON'
print(a,id(a))
print(a.lower(),id(a.lower()))
# HELLO,PYTHON 2564162926448
# hello,python 2564162926512
print(a==s.upper())
print(a is s.upper())
# True
# False
#内容相同，地址不同
 
s1='asfJSEOFH'
print(s1.swapcase())
print(s1.capitalize())
s2='sdjf ddjo EJOSD CNDDScjd'
print(s2.title())
# ASFjseofh
# Asfjseofh
# Sdjf Ddjo Ejosd Cnddscjd
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字符串内容对齐

字符串内容对齐操作方法

宽度，指定填充符

s='hello,Python'
print(s.center(20,'*'))
# ****hello,Python****
print(s.ljust(20,'*'))
print(s.ljust(10,'*'))
print(s.ljust(20))
# hello,Python********
# hello,Python
# hello,Python
print(s.rjust(20,'*'))
print(s.rjust(20))
print(s.rjust(10))
# ********hello,Python
#         hello,Python
# hello,Python
print(s.zfill(20))
print('-9010'.zfill(8))
# 00000000hello,Python
# -0009010
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字符串的劈分

字符串劈分操作的方法

s='hello world python'
lst=s.split()
print(lst)
s1='hello|world|python'
print(s1.split())
print(s1.split(sep='|'))#让分隔符为竖线
print(s1.split(sep='|',maxsplit=1))#只分一次
# ['hello', 'world', 'python']
# ['hello|world|python']
# ['hello', 'world', 'python']
# ['hello', 'world|python']
 
s='hello world python'
lst=s.rsplit()
print(lst)
s1='hello|world|python'
print(s1.rsplit())
print(s1.rsplit(sep='|'))#让分隔符为竖线
print(s1.rsplit(sep='|',maxsplit=1)) #从右侧开始劈分，只分一次
# ['hello', 'world', 'python']
# ['hello|world|python']
# ['hello', 'world', 'python']
# ['hello|world', 'python']
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字符串判断

判断字符串操作的方法

s='hello,python'
print(s.isidentifier())
s='hello2341_python'#字母数字下划线
print(s.isidentifier())
# False
# True
s=' \n \t'
print(s.isspace())
# True
s='dsjfSDLFJ'
print(s.isalpha())
s='dsf3'
print(s.isalpha())
# True
# False
s='238509'
print(s.isdecimal())
s='九02347'
print(s.isdecimal())
# True
# False
s='32840四五十四'
print(s.isnumeric())
# True
s='sdjf324'
print(s.isalnum())
# True
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字符串替换和合并

s='hello,python,python,python'
print(s.replace('python','c++'))
s='hello,python,python,python'
print(s.replace('python','c++',2))
# hello,c++,c++,c++
# hello,c++,c++,python
 
lst=['hello','java','python']
print('|'.join(lst))
print(''.join(lst))
# hello|java|python
# hellojavapython
t=('hello','java','python')
print('|'.join(t))
print(''.join(t))
# hello|java|python
# hellojavapython
print('*'.join('Python'))
# P*y*t*h*o*n
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