Making closures in loop ?

Hi there,

I want to create a list of functions with something like:

closures = [lambda x: i*x for i in range(10)]

so that
closures[0] = 0*x
closures[1] = 1*x
closures[2] = 2*x
...
closures[9] = 9*x

For some reason, all elements seem to bind the last value of i, that is closures[j] = 9*x for all j, not only 9. Any ideas of why does this happen, and how should I make it work as intended ?

George

That is how it is bound.

Check what jeremy has got to say.

You can get it to work the way you want by passing in i as a default parameter, i.e.:



This was the standard way to simulate closures in Python prior to 2.1, when it did not have the new scoping rules.

Dave - The Developers' Coach

I was sure there was a way around it; thanks a lot Dave !

George