Explanation of this Python language feature? [x for x in x for x in x] (to flatten a nested list)
Terry Reedy
tjreedy at udel.edu
Tue Mar 25 02:31:46 CET 2014
On 3/24/2014 8:28 PM, Chris Angelico wrote:
> Pure functional programming, from what I understand, doesn't *have*
> variables other than function arguments.
function *parameters*, if in the 'variable = name' camp
> So the way to implement "x = 1" is to call a subfunction
with a parameter named 'x'
> with an argument of 1
Funny, I was just thinking about that last night. I really learned it
when trying to translate python code to the scheme dialect racket.
import math as m
s = m.sqrt(2)
a = m.sin(s) + m.cos(s)
del s # to be exactly equivalent to the below, but not needed
b = (lambda x: m.sin(x) + m.cos(x))(m.sqrt(2))
print(a,b)
>>>
1.14370964075811 1.14370964075811
--
Terry Jan Reedy
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