Count frequencies of all elements in array in Python using collections module
Given an unsorted array of n integers which can contains n integers. Count frequency of all elements that are present in array.
Examples:
Input : arr[] = [1, 1, 1, 1, 2, 2, 2, 2, 3, 3, 4, 5, 5]
Output : 1 -> 4
2 -> 4
3 -> 2
4 -> 1
5 -> 2
This problem can be solved in many ways, refer Count frequencies of all elements in array link. In Python, we can quickly solve this problem in using Collections module.
# Function to count frequency of each element import collections # it returns a dictionary data structure whose # keys are array elements and values are their # corresponding frequencies {1: 4, 2: 4, 3: 2, # 5: 2, 4: 1} def CountFrequency(arr): return collections.Counter(arr) # Driver function if __name__ == "__main__": arr = [1, 1, 1, 1, 2, 2, 2, 2, 3, 3, 4, 5, 5] freq = CountFrequency(arr) # iterate dictionary named as freq to print # count of each element for key, value in freq.iteritems(): print key, " -> ", value |
chevron_right
filter_none
Output:
1 -> 4 2 -> 4 3 -> 2 4 -> 1 5 -> 2
Related Article :
Counting the frequencies in a list using dictionary in Python
This article is contributed by Shashank Mishra (Gullu). If you like GeeksforGeeks and would like to contribute, you can also write an article using contribute.geeksforgeeks.org or mail your article to contribute@geeksforgeeks.org. See your article appearing on the GeeksforGeeks main page and help other Geeks.
Please write comments if you find anything incorrect, or you want to share more information about the topic discussed above.
Recommended Posts:
- Count frequencies of all elements in array in O(1) extra space and O(n) time
- Elements of first array that have more frequencies
- Array elements with prime frequencies
- Counting frequencies of array elements
- Range Queries for Frequencies of array elements
- Find array elements with frequencies in range [l , r]
- Sum of elements in an array with frequencies greater than or equal to that element
- Count distinct elements in an array in Python
- Python | Count the array elements with factors less than or equal to the factors of given x
- Count number of elements between two given elements in array
- Count array elements that divide the sum of all other elements
- For each element in 1st array count elements less than or equal to it in 2nd array | Set 2
- For each element in 1st array count elements less than or equal to it in 2nd array
- Count distinct elements in an array
- Count elements present in first array but not in second
- Find the count of subsequences where each element is divisible by K
- Generate an array having Bitwise AND of the previous and the next element
- Check whether bitwise AND of N numbers is Even or Odd
- Minimum cost of choosing 3 increasing elements in an array of size N
- Product of elements in an array having prime frequency