Sort list by indexes

OSCC · Python, List · Nov 2, 2020

Sorts 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.
def sort_by_indexes(lst, indexes, reverse=False):
  return [val for (_, val) in sorted(zip(indexes, lst), key=lambda x: \
          x[0], reverse=reverse)]
a = ['eggs', 'bread', 'oranges', 'jam', 'apples', 'milk']
b = [3, 2, 6, 4, 1, 5]
sort_by_indexes(a, b) # ['apples', 'bread', 'eggs', 'jam', 'milk', 'oranges']
sort_by_indexes(a, b, True)
# ['oranges', 'milk', 'jam', 'eggs', 'bread', 'apples']

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