How to check if a list contains an item

[online.service.com]

python doesn't have a list.contains() method?


thanks

 

[Esmail]

python doesn't have a list.contains() method?

How about the 'in' operator?

In [1]: l1=['aa', 'bb', 'cc']

In [2]: 'aa' in l1
Out[2]: True

In [3]: 'ab' in l1
Out[3]: False

In [4]: 'cc' in l1
Out[4]: True

Will this help?

Esmail

 

[Peter Otten]

python doesn't have a list.contains() method?

It has. It's called list.__contains__() and used indirectly through the 'in'
operator:

"red" in ["red", "green", "blue"] True
"yellow" in ["red", "green", "blue"]

False

 

[MRAB]

python doesn't have a list.contains() method?

It does have a __contains__ method, but that's not called directly. Use
"item in my_list" instead (and the opposite is "item not in my_list").

 

[Tim Chase]

python doesn't have a list.contains() method?

Because it doesn't need one?

>>> x = [1,2,3,4]
>>> 2 in x True
>>> 42 in x

False


pedantic side-note, objects can have a __contains__ method which
is used under the covers for "in" testing, so your custom objects
can also test for containment.

-tkc