Python Multiple Assignment Is a Puzzle

Re:Python Multiple Assignment Is a Puzzle by zebulanmcranahn on Sunday July 27, 2014 @01:32PM (#8093355)

  def firstMissingPositive(A):
      try:
          for x in range(1, max(A)+1):
              if x not in A: return x
      except: return A

  def firstMissingPositive(A):
      try: return next(x for x in range(1, max(A)+1) if x not in A)
      except: return A

Two above return:

  print(firstMissingPositive([4,2,5,7,1])) # 3
  print(firstMissingPositive([4,100]))     # 1
  print(firstMissingPositive([]))          # []
  print(firstMissingPositive([5]))         # 1

I wasn't sure what [5] or [] were supposed to return so maybe I'm still wrong? Had never heard of this question before, thought I'd try it out.

Thanks for the reply, very informative.

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Re:Python Multiple Assignment Is a Puzzle by TheLoneWolfling on Sunday July 27, 2014 @05:11PM (#8093984)

You really should change "except" to "except ValueError" there.

Also, I suggest first converting A to a set. Just "A = set(A)" would work.

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Re:Python Multiple Assignment Is a Puzzle by yeukhon on Sunday July 27, 2014 @02:55PM (#8093613)

HN is not really for code review, but why are you using try and except here??

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Re:Python Multiple Assignment Is a Puzzle by TheLoneWolfling on Sunday July 27, 2014 @05:07PM (#8093972)

Python is designed for it, and it makes it cleaner, so why not?

EAFP: Easier to ask for forgiveness than permission

That being said, just a blanket except is a bad idea.

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Re:Python Multiple Assignment Is a Puzzle by zebulanmcranahn on Monday July 28, 2014 @12:51AM (#8095233)

Thanks for the ValueError tip. I added it as well as a TypeError just in case the input comes in as a string. My skills are beginner level at best, tips like yours help a lot!

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