Find index of item in list

Steven Bethard steven.bethard at gmail.com
Tue Dec 7 21:07:47 CET 2004


wes weston wrote:
> Sean Berry wrote:
> 
>> myList = ['cat', 'dog', 'mouse' ... 'bear']
>>
>> what is the easiest way to find out what index 'dog' is at?
> 
>  >>> myList = ['cat', 'dog', 'mouse','bear']
>  >>> myList.index('dog')
> 1
>  >>>

Yup, list.index is almost certainly what you want, though it's worth 
mentioning that list.index returns the *first* occurrence of the item in 
the list.  You can get later items by supplying an appropriate starting 
index:

 >>> my_list = ['cat', 'dog', 'mouse', 'bear', 'dog']
 >>> my_list.index('dog')
1
 >>> my_list.index('dog', 2)
4
 >>> my_list.index('dog', 5)
Traceback (most recent call last):
   File "<interactive input>", line 1, in ?
ValueError: list.index(x): x not in list

Steve



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