# Python – Retain records with N occurrences of K

Somtimes, while working with Python tuples list, we can have a problem in which we need to perform retention of all the records where occurrences of K is N times. This kind of problem can come in domains such as web development and day-day programming. Let’s discuss certain ways in which this task can be performed.

Input : test_list = [(4, 5, 5, 4), (5, 4, 3)], K = 5, N = 2
Output : [(4, 5, 5, 4)]

Input : test_list = [(4, 5, 5, 4), (5, 4, 3)], K = 5, N = 3
Output : []

Method #1 : Using list comprehension + `count()`
The combination of above functions can be used to solve this problem. In this, we perform the task of counting occurrences and conditions and iterations using list comprehension.

 `# Python3 code to demonstrate working of  ` `# Retain records with N occurrences of K ` `# Using count() + list comprehension ` ` `  `# initializing list ` `test_list ``=` `[(``4``, ``5``, ``6``, ``4``, ``4``), (``4``, ``4``, ``3``), (``4``, ``4``, ``4``), (``3``, ``4``, ``9``)] ` ` `  `# printing original list ` `print``(``"The original list is : "` `+` `str``(test_list)) ` ` `  `# initializing K ` `K ``=` `4` ` `  `# initializing N  ` `N ``=` `3` ` `  `# Retain records with N occurrences of K ` `# Using count() + list comprehension ` `res ``=` `[ele ``for` `ele ``in` `test_list ``if` `ele.count(K) ``=``=` `N] ` ` `  `# printing result  ` `print``(``"Filtered tuples : "` `+` `str``(res))  `

Output :

```The original list is : [(4, 5, 6, 4, 4), (4, 4, 3), (4, 4, 4), (3, 4, 9)]
Filtered tuples : [(4, 5, 6, 4, 4), (4, 4, 4)]
```

Method #2 : Using `list comprehension + sum()`
The combination of above functions can be used to solve this problem. In this, we perform the task of computing summation count of K using sum().

 `# Python3 code to demonstrate working of  ` `# Retain records with N occurrences of K ` `# Using list comprehension + sum() ` ` `  `# initializing list ` `test_list ``=` `[(``4``, ``5``, ``6``, ``4``, ``4``), (``4``, ``4``, ``3``), (``4``, ``4``, ``4``), (``3``, ``4``, ``9``)] ` ` `  `# printing original list ` `print``(``"The original list is : "` `+` `str``(test_list)) ` ` `  `# initializing K ` `K ``=` `4` ` `  `# initializing N  ` `N ``=` `3` ` `  `# Retain records with N occurrences of K ` `# Using list comprehension + sum() ` `res ``=` `[ele ``for` `ele ``in` `test_list ``if` `sum``(cnt ``=``=` `K ``for` `cnt ``in` `ele) ``=``=` `N] ` ` `  `# printing result  ` `print``(``"Filtered tuples : "` `+` `str``(res))  `

Output :

```The original list is : [(4, 5, 6, 4, 4), (4, 4, 3), (4, 4, 4), (3, 4, 9)]
Filtered tuples : [(4, 5, 6, 4, 4), (4, 4, 4)]
```

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