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Python: Merge two or more lists into a list of lists

Python List: Exercise - 215 with Solution

Write a Python program to merge two or more lists into a list of lists, combining elements from each of the input lists based on their positions.

Merges two or more lists into a list of lists, combining elements from each of the input lists based on their positions.

  • Use max() combined with a list comprehension to get the length of the longest list in the arguments.
  • Use range() in combination with the max_length variable to loop as many times as there are elements in the longest list
  • If a list is shorter than max_length, use fill_value for the remaining items (defaults to None)
  • zip() and itertools.zip_longest() provide similar functionality to this snippet

Sample Solution:

Python Code:

def merge_lists(*args, fill_value = None):
  max_length = max([len(lst) for lst in args])
  result = []
  for i in range(max_length):
    result.append([
      args[k][i] if i < len(args[k]) else fill_value for k in range(len(args))
    ])
  return result
print("After merging lists into a list of lists:")
print(merge_lists(['a', 'b'], [1, 2], [True, False]))  
print(merge_lists(['a'], [1, 2], [True, False]))  
print(merge_lists(['a'], [1, 2], [True, False], fill_value = '_'))

Sample Output:

After merging lists into a list of lists:
[['a', 1, True], ['b', 2, False]]
[['a', 1, True], [None, 2, False]]
[['a', 1, True], ['_', 2, False]]

Flowchart:

Flowchart: Merge two or more lists into a list of lists.

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Python Code Editor:

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Next: Write a Python program to group the elements of a list based on the given function and returns the count of elements in each group.

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Python: Tips of the Day

Big Number Readability:

you can separate zeros with underscore (_)

print(2_000_000)
print(2_000_000 +1)

Output:

2000000
2000001