How to find duplicates values in list Python -

How to find duplicates values in list Python -

i wondering how can know if when user inputs value, value exists in list.

for example;

lis = ['foo', 'boo', 'hoo']

user inputs:

'boo'

now question how can tell user value exists within list.

use in operator:

>>> lis = ['foo', 'boo', 'hoo'] >>> 'boo' in lis true >>> 'zoo' in lis false

you can utilize lis.index homecoming index of element.

>>> lis.index('boo') 1

if element not found, raise valueerror:

>>> lis.index('zoo') traceback (most recent phone call last): file "<stdin>", line 1, in <module> valueerror: 'zoo' not in list

update

as nick t commented, if don't care order of items, can utilize set:

>>> lis = {'foo', 'boo', 'hoo'} # set literal == set(['foo', 'boo', 'hoo']) >>> lis.add('foo') # duplicated item not added. >>> lis {'boo', 'hoo', 'foo'}

python list duplicates