lambda in list comprehension acting funny

88888 Dihedral dihedral88888 at googlemail.com
Thu Jul 12 05:39:45 CEST 2012


On Thursday, July 12, 2012 12:34:33 AM UTC+8, Ian wrote:
> On Wed, Jul 11, 2012 at 4:28 AM, Colin J. Williams <cjw at ncf.ca> wrote:
> > I don't understand why you would expect 1, 2, 4.
> 
> Because:
> 
> funcs[0](2) == 2 ** 0 == 1
> funcs[1](2) == 2 ** 1 == 2
> funcs[2](2) == 2 ** 2 == 4
> 
> > Perhaps parentheses will help the order of evaluation:
> >
> > funcs = [(lambda x: x**i) for i in range( 5 )]
> >
> > This gives:
> > 1
> > 16
> > 81
> 
> No, that gives 16, 16, 16 just like the original.  I don't understand
> why you would expect 1, 16, 81, unless you have misread the code.

I'll contribute my way of python programming:

def powerb(x, b): # 
     return x**b


One functor is enough!



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