[Python-Dev] functools.compose to chain functions together (original) (raw)

Xavier Morel catch-all at masklinn.net
Fri Aug 14 20:58:22 CEST 2009

On 14 Aug 2009, at 20:39 , Jason R. Coombs wrote:

I've heard it said that Python is not a functional language, but if that were really the case, then functools would not exist. In addition to the example described above, I've had multiple occasions where having a general purpose function composition function would have simplified the implementation by providing a basic functional construct.

It's not like a basic variable-arity composition function is hard to
implement though, it's basically:

 def compose(*funcs):
     return reduce(lambda f1, f2:
                       lambda v:
                           f1(f2(v)),
                   funcs)

it'll turn compose(a, b, c, d)(value) into a(b(c(d(value))))

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