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Python: Sort one list based on another list containing the desired indexes

Python List: Exercise - 218 with Solution

Write a Python program to sort one list based on another list containing the desired indexes.

  • Use zip() and sorted() to combine and sort the two lists, based on the values of indexes.
  • Use a list comprehension to get the first element of each pair from the result
  • Use the reverse parameter in sorted() to sort the dictionary in reverse order, based on the third argument

Sample Solution:

Python Code:

def sort_by_indexes(lst, indexes, reverse=False):
  return [val for (_, val) in sorted(zip(indexes, lst), key=lambda x: \
          x[0], reverse=reverse)]

l1 = ['eggs', 'bread', 'oranges', 'jam', 'apples', 'milk']
l2 = [3, 2, 6, 4, 1, 5]
print(sort_by_indexes(l1, l2))  
print(sort_by_indexes(l1, l2, True))

Sample Output:

['apples', 'bread', 'eggs', 'jam', 'milk', 'oranges']
['oranges', 'milk', 'jam', 'eggs', 'bread', 'apples']

Flowchart:

Flowchart: Sort one list based on another list containing the desired indexes.

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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