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Groups > comp.lang.python > #105840

Why lambda in loop requires default?

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Given that Python, like Ruby, is an object-oriented language why doesn't 
this:

def m():
   a = []
   for i in range(3): a.append(lambda: i)
   return a

b = m()
for n in range(3): print(b[n]())  # =>  2  2  2

... work the same as this in Ruby:

def m
   a = []
   (0..2).each {|i| a << ->(){i}}
   a
end

aa = m
(0..2).each {|n| puts aa[n].()}  # =>  0  1  2


lambda i=i: i

... is needed to make it work in Python. Just wondered why?

gvim

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Why lambda in loop requires default? gvim <gvimrc@gmail.com> - 2016-03-27 02:46 +0100
  Re: Why lambda in loop requires default? Jussi Piitulainen <jussi.piitulainen@helsinki.fi> - 2016-03-27 17:16 +0300
  Re: Why lambda in loop requires default? Jussi Piitulainen <jussi.piitulainen@helsinki.fi> - 2016-03-27 18:15 +0300
  Re: Why lambda in loop requires default? Ned Batchelder <ned@nedbatchelder.com> - 2016-03-27 08:29 -0700

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