查找和索引之间的差异

Question

我是python新手，不太了解find和index之间的区别。

>>> line
'hi, this is ABC oh my god!!'
>>> line.find("o")
16
>>> line.index("o")
16

它们总是返回相同的结果。 谢谢！！

Answer 1

当找不到子字符串时，^{}返回-1。

>>> line = 'hi, this is ABC oh my god!!'
>>> line.find('?')
-1

当^{}提高ValueError时：

>>> line.index('?')
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
ValueError: substring not found

如果找到子字符串，这两个函数的行为相同。

Answer 2

此外，find仅适用于字符串，其中as index可用于列表、元组和字符串

>>> somelist
['Ok', "let's", 'try', 'this', 'out']
>>> type(somelist)
<class 'list'>

>>> somelist.index("try")
2

>>> somelist.find("try")
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
AttributeError: 'list' object has no attribute 'find'

>>> sometuple
('Ok', "let's", 'try', 'this', 'out')
>>> type(sometuple)
<class 'tuple'>

>>> sometuple.index("try")
2

>>> sometuple.find("try")
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
AttributeError: 'tuple' object has no attribute 'find'

>>> somelist2
"Ok let's try this"
>>> type(somelist2)
<class 'str'>

>>> somelist2.index("try")
9
>>> somelist2.find("try")
9

>>> somelist2.find("t")
5
>>> somelist2.index("t")
5