Is there a short contains function for lists

Question

I see people are using any to gather another list to see if an item exists in a list  but is there a quick way to just do    if list contains myItem         do something

User · Accepted Answer

You can use this syntax   if myItem in list        do something   Also  inverse operator   if myItem not in list        do something   It s work fine for lists  tuples  sets and dicts  check keys    Note that this is an O n  operation in lists and tuples  but an O 1  operation in sets and dicts

User · Answer

The list method index will return -1 if the item is not present  and will return the index of the item in the list if it is present  Alternatively in an if statement you can do the following   if myItem in list       do things   You can also check if an element is not in a list with the following if statement   if myItem not in list       do things

User · Answer

In addition to what other have said  you may also be interested to know that what in does is to call the list   contains   method  that you can define on any class you write and can get extremely handy to use python at his full extent   nbsp   A dumb use may be    gt  gt  gt  class ContainsEverything      def   init   self           return None     def   contains   self   elem    k           return True    gt  gt  gt  a   ContainsEverything    gt  gt  gt  3 in a True  gt  gt  gt  a in a True  gt  gt  gt  False in a True  gt  gt  gt  False not in a False  gt  gt  gt

User · Answer

I came up with this one liner recently for getting True if a list contains any number of occurrences of an item  or False if it contains no occurrences or nothing at all  Using next      gives this a default return value  False  and means it should run significantly faster than running the whole list comprehension   list does contain   next  True for item in list to test if item    test item   False

[python] Is there a short contains function for lists?

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