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Python: Frequency of the elements in a given list of lists

Python List: Exercise - 143 with Solution

Write a Python program to get the frequency of the elements in a given list of lists.

Sample Solution:

Python Code:

def count_elements_lists(nums):
    nums = [item for sublist in nums for item in sublist]
    dic_data = {}
    for num in nums:
        if num in dic_data.keys():
            dic_data[num] += 1
        else:
            key = num
            value = 1
            dic_data[key] = value
    return dic_data

nums = [
        [1,2,3,2],
        [4,5,6,2],
        [7,8,9,5],
       ]    
print("Original list of lists:")
print(nums)
print("\nFrequency of the elements in the said list of lists:")
print(count_elements_lists(nums))

Sample Output:

Original list of lists:
[[1, 2, 3, 2], [4, 5, 6, 2], [7, 8, 9, 5]]

Frequency of the elements in the said list of lists:
{1: 1, 2: 3, 3: 1, 4: 1, 5: 2, 6: 1, 7: 1, 8: 1, 9: 1}

Flowchart:

Flowchart: Frequency of the elements in a given list of lists.

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Python Code Editor:

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Previous: Write a Python program to sum a specific column of a list in a given list of lists.
Next: Write a Python program to extract every first or specified element from a given two-dimensional list.

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Python: Tips of the Day

Find current directory and file's directory:

To get the full path to the directory a Python file is contained in, write this in that file:

import os 
dir_path = os.path.dirname(os.path.realpath(__file__))

(Note that the incantation above won't work if you've already used os.chdir() to change your current working directory, since the value of the __file__ constant is relative to the current working directory and is not changed by an os.chdir() call.)

To get the current working directory use

import os
cwd = os.getcwd()

Documentation references for the modules, constants and functions used above:

  • The os and os.path modules.
  • The __file__ constant
  • os.path.realpath(path) (returns "the canonical path of the specified filename, eliminating any symbolic links encountered in the path")
  • os.path.dirname(path) (returns "the directory name of pathname path")
  • os.getcwd() (returns "a string representing the current working directory")
  • os.chdir(path) ("change the current working directory to path")

Ref: https://bit.ly/3fy0R6m