"Diez B. Roggisch" <de...@nospam.web.de> writes: > enzo michelangeli schrieb: >> 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.) > > You need to capture n into the closure of the lambda: > > f = [lambda x, n=n: x+j for j in xrange(n)] >
But be careful using such a technique with mutable arguments... -- http://mail.python.org/mailman/listinfo/python-list
