mycsmajor
Python problem 1 of 30

Reverse the words

  • Python
  • Easy

Write reverse_words(s) that returns the words of s in reverse order, separated by single spaces. Extra spaces in the input should not matter.

reverse_words("one cs problem")
# "problem cs one"

reverse_words("  hello   world ")
# "world hello"
Show hint

str.split() with no arguments splits on any run of whitespace and drops empty pieces.

Show solution 
def reverse_words(s):
    return " ".join(s.split()[::-1])

s.split() gives a clean list of words, [::-1] reverses it, and " ".join glues it back with single spaces. Runs in O(n) time.

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