Lesser known parts of Python standard library

Re:Lesser known parts of Python standard library – Trickster... by hansvm on Thursday September 05, 2024 @02:29PM (#41459237)

Sometimes mutations in comprehensions are very expressive.

  def scan(items, f, initial):
    x = initial
    return (x := f(x, y) for y in items)

There are lots of other short ways to write `scan`, but I don't think any of them map so clearly to a naive definition of what it's supposed to do.

[ Parent | on HN ]

Re:Lesser known parts of Python standard library – Trickster... by judicious on Thursday September 05, 2024 @03:03PM (#41459529)

That's incredibly clever, generators are underrated. I once challenged my friend to do leetcode problems with only expressions. Here's levenshtein distance, however it's incredibly clunky.

  levenshtein_distance = lambda s1, s2: [matrix := [[0] * (len(s2) + 1) for _ in 
  range(len(s1) + 1)], [
          [
              (matrix[i].__setitem__(j, min(matrix[i-1][j] + 1, matrix[i][j-1] + 
  1, matrix[i-1][j-1] + (0 if s1[i-1] == s2[j-1] else 1))), matrix[i][-1])[1]
              for j in range(1, len(s2) + 1)
         ]
         for i in range(1, len(s1) + 1)
     ], matrix[-1][-1]][-1]

[ Parent | on HN ]