How to create a list of functions depending on a parameter?

enzo michelangeli enzomich at gmail.com
Tue May 26 10:51:20 CEST 2009


Let's suppose I want to create a list of n functions of a single
argument, returning the sum between argument and index in the list, so
that e.g.:

f[0](10) will return 10
f[3](12) will return 15

...and so on. I had naively though of coding:

 f = [lambda x: x+j for j in range(n)]

Unfortunately, each function in the list f[]() behaves as a closure,
and f[k](p) does NOT return p+k but p+j (for whatever value j has at
the moment: typically n, the last value assumed by j in the list
comprehension loop).

Is there a way of achieving my goal? (Of course, n is not a constant
known in advance, so I can't manually unroll the loop.)

Thanks for any suggestion.



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