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A comment on Ask HN: If you're “ridiculously in love with Python”, do you even know it well?. Parent comment

Re:Ask HN: If you're “ridiculously in love with Python”, do ... by hyperbovine on Wednesday January 21, 2015 @10:34AM (#8923488)
Can someone elaborate on this? I thought I had seen all the Python idioms but this one is new to me.
[ Parent | on HN ]
Re:Ask HN: If you're “ridiculously in love with Python”, do ... by sherjilozair on Wednesday January 21, 2015 @10:40AM (#8923515) 

  def a(b=[]):
      b.append(1)
      print b
Now if you do,

  a()
  a()
you might expect to see

  [1]
  [1]
but you will actually see

  [1]
  [1, 1]
The list is not created at function call time, but at function definition time.
[ Parent | on HN ]
Re:Ask HN: If you're “ridiculously in love with Python”, do ... by ShinyCyril on Wednesday January 21, 2015 @11:46AM (#8923868)
This has bitten me more times than I'd care to admit.
[ Parent | on HN ]