Python | List Merging | Programming Tutorials

Introduction

In Python, we can merge two or more lists into a single list using various methods. One such method is to combine elements from each of the input lists based on their positions. In this challenge, you will be tasked with writing a function that merges multiple lists into a list of lists.

Skills Graph

%%%%{init: {'theme':'neutral'}}%%%% flowchart RL python(("`Python`")) -.-> python/BasicConceptsGroup(["`Basic Concepts`"]) python(("`Python`")) -.-> python/FunctionsGroup(["`Functions`"]) python(("`Python`")) -.-> python/ControlFlowGroup(["`Control Flow`"]) python(("`Python`")) -.-> python/DataStructuresGroup(["`Data Structures`"]) python/BasicConceptsGroup -.-> python/comments("`Comments`") python/FunctionsGroup -.-> python/keyword_arguments("`Keyword Arguments`") python/BasicConceptsGroup -.-> python/booleans("`Booleans`") python/ControlFlowGroup -.-> python/conditional_statements("`Conditional Statements`") python/ControlFlowGroup -.-> python/for_loops("`For Loops`") python/ControlFlowGroup -.-> python/list_comprehensions("`List Comprehensions`") python/DataStructuresGroup -.-> python/lists("`Lists`") python/DataStructuresGroup -.-> python/tuples("`Tuples`") python/FunctionsGroup -.-> python/function_definition("`Function Definition`") python/FunctionsGroup -.-> python/default_arguments("`Default Arguments`") python/FunctionsGroup -.-> python/build_in_functions("`Build-in Functions`") subgraph Lab Skills python/comments -.-> lab-13691{{"`Merging Multiple Lists in Python`"}} python/keyword_arguments -.-> lab-13691{{"`Merging Multiple Lists in Python`"}} python/booleans -.-> lab-13691{{"`Merging Multiple Lists in Python`"}} python/conditional_statements -.-> lab-13691{{"`Merging Multiple Lists in Python`"}} python/for_loops -.-> lab-13691{{"`Merging Multiple Lists in Python`"}} python/list_comprehensions -.-> lab-13691{{"`Merging Multiple Lists in Python`"}} python/lists -.-> lab-13691{{"`Merging Multiple Lists in Python`"}} python/tuples -.-> lab-13691{{"`Merging Multiple Lists in Python`"}} python/function_definition -.-> lab-13691{{"`Merging Multiple Lists in Python`"}} python/default_arguments -.-> lab-13691{{"`Merging Multiple Lists in Python`"}} python/build_in_functions -.-> lab-13691{{"`Merging Multiple Lists in Python`"}} end

Merge Lists

Write a function called merge(*args, fill_value=None) that takes in two or more lists as arguments and returns a list of lists. The function should combine elements from each of the input lists based on their positions. If a list is shorter than the longest list, the function should use fill_value for the remaining items. If fill_value is not provided, it should default to None.

Your task is to implement the merge() function.

def merge(*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

merge(['a', 'b'], [1, 2], [True, False]) ## [['a', 1, True], ['b', 2, False]]
merge(['a'], [1, 2], [True, False]) ## [['a', 1, True], [None, 2, False]]
merge(['a'], [1, 2], [True, False], fill_value = '_')
## [['a', 1, True], ['_', 2, False]]

Summary

In this challenge, you learned how to merge two or more lists into a list of lists in Python. You also learned how to use the max() function, list comprehension, and the range() function to solve the problem. Remember to use the fill_value parameter to fill in the missing values in the shorter lists.

Merging Multiple Lists in Python

Introduction

Skills Graph

Merge Lists

Summary

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