python学习笔记之基础操作（二）字符串操作（2）

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#二：替换操作
#replace():替换指定字符串
test = "123abcefsdfa"
print(test.replace("123","___"))

___abcefsdfa

#swapcase():转换大小写:
test = "asdfgVBNMK"
print(test.swapcase())

ASDFGvbnmk

#upper(),lower()
print(test.upper())
print(test.lower())

ASDFGVBNMK
asdfgvbnmk

#三，分割操作
#split():按照指定字符串分割字符，可以指定分割的数量
test = "123,456,789"
print(test.split(","))
print(test.split(",",1))

['123', '456', '789']
['123', '456,789']

#partition()按照指定字符串分割为两部分,包含分隔符
#rpartition()，右面第一个开始分割
print(test.partition(","))
print(test.rpartition(","))

('123', ',', '456,789')
('123,456', ',', '789')

#四：查找操作
#find():找不到返回-1
test = "12345672"
print(test.find("2"))
print(test.rfind("2"))
print(test.find("a"))

1
7
-1

#index同上，不过返回错误找不到的话
print(test.index("2"))
print(test.rindex("2"))
print(test.index("a"))

1
7



---------------------------------------------------------------------------

ValueError                                Traceback (most recent call last)

<ipython-input-17-af7b2106d969> in <module>()
      2 print(test.index("2"))
      3 print(test.rindex("2"))
----> 4 print(test.index("a"))


ValueError: substring not found