Check if an item in a Python list

This tutorial shows examples of checking if an item is in a Python list.

Method 1:

item in list_name

Method 2:

list_name.index(item)

Method 3:

list_name.count(item)

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Example for method 1: Check if an item in a list

The following code checks if the item of number 6 is in a list.

# creat a list
list_1=[7, 6, 5, 4] 

# check if the item of 6 is in the list
6 in list_1

The following is the output, which shows True.

True

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Example for method 2: locate an item

The following Python code checks the location of an item in a list.

# check if item 7 is in the list
[7, 6, 5, 4].index(7) 

# check if item 8 is in the list
[7, 6, 5, 4].index(8) 

The output are 0 (which is the location of 7) and ValueError.

0

ValueError: 8 is not in list

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Example for method 3: count the number

The following code counts the number of an item in a list.

# Create a list
list_2=[7, 6, 5, 4, 6]

# count the number of the item in the list
list_2.count(6)

The following is the output. It indicates that the number is 2 since there are 2 6 in the list.

2