# Python List Function | count ()

Python Methods and Functions

Syntax :

` list_name.count (object) `

Parameters :

` Object is the things whose count is to be returned. `

Returns :

` count () method returns count of how many times obj occurs in list. `

Exception:

` If more then 1 parameter is passed in count () method, it returns a TypeError.`

Code # 1

 ` # Python3 program for counting the number of times ` ` # object appears in the list with using the count () method `   ` list1 ` ` = ` ` [` ` 1 ` `, ` ` 1 ` `, ` ` 1 ` `, ` ` 2 ` `, ` ` 3 ` ` , ` 2 `, ` ` 1 ` `] `   ` # Counts how many times 1 appears in list 1 ` ` print ` ` (list1.count (` ` 1 ` `)) `   ` list2 ` ` = ` ` [` ` 'a' ` ` , ` ` 'a' ` `, ` `' a' ` `, ` ` 'b' ` `, ` `' b' ` `, ` ` 'a' ` `, ` `' c' ` `, ` ` 'b' ` `] `   ` # Counts how many times “b” appears in the list ` ` print ` ` (list2.count (` ` 'b '` `)) ` ` `  ` list3 ` ` = ` ` [` ` 'Cat' ` `, ` ` 'Bat' ` `, ` `' Sat' ` `, ` ` 'Cat' ` `, ` ` 'cat' ` `, ` `' Mat' ` `] `   ` # Counts how many times & # 39; Cat & # 39; appears in list 3 ` ` print ` ` (list3.count (` `' Cat' ` `)) `

Output:

` 4 3 2 `

Code # 2: TypeError

` `

` # Python3 demo # error in count () method   list1 = [ 1 , 1 , 1 , 2 , 3 , 2 , 1 ]    # Error passing two parameters. print (list1.count ( 1 , 2 ))  `

` `

Output:

` Traceback (most recent call last): File "/home/41d2d7646b4b549b399b0dfe29e38c53.py", line 7, in print (list1. count (1, 2)) TypeError: count () takes exactly one argument (2 given) `

Code # 3

 ` # Python3 program to count the number of times ` ` # object appears in the list using the count () method ` ` `  ` list1 ` ` = ` ` [ (` ` 'Cat' ` `, ` `' Bat' ` `), (` ` 'Sat' ` `, ` `' Cat' ` `), (` ` 'Cat' ` `, ` ` 'Bat' ` `), ` ` ` ` (` ` 'Cat' ` `, ` `' Bat' ` `, ` ` 'Sat' ` `), [` ` 1 ` `, ` ` 2 ` `], [` ` 1 ` `, ` ` 2 ` `, ` 3 `], [` ` 1 ` `, ` ` 2 ` `]] `   ` # Counts how many times "Cat" appears in the list ` ` print ` ` (list1.count ((` ` 'Cat' ` `, ` ` 'Bat' ` `))) ` ` `  ` # Count the number of times sublisted ` ` # & # 39; [1, 2] & # 39; appears in list 1 ` ` print ` ` (list1.count ([` ` 1 ` `, ` ` 2 ` `])) `

Output:

` 2 2 `

Practical Application:

Let's say we want to count each item in a list and store in another list, or say a dictionary.

 ` # Python3 program for counting the number of times ` ` # object appears in the list using the count () method `   ` lst ` ` = ` ` [` ` 'Cat' ` `, ` `' Bat' ` `, ` ` 'Sat' ` `, ` `' Cat' ` `, ` ` 'Mat' ` `, ` `' Cat' ` `, ` ` 'Sat' ` `] `   ` # To see the number of occurrences ` ` # of each item in the list ` ` print ` ` ([[l, lst.count (l)] ` ` for ` ` l ` ` in ` ` set ` ` (lst)]) `   ` # To see the number of occurrences ` ` # of each item in the dictionary ` ` print ` ` (` ` dict ` ` ((l, lst.count (l)) ` ` for ` ` l ` ` in ` ` set ` ` (lst))) `

Output:

` [['Mat', 1], [' Cat', 3], ['Sat', 2], [' Bat', 1]] {'Bat': 1,' Cat': 3, 'Sat': 2,' Mat': 1} `