On 12 September 2012 14:25, Libra <librar...@gmail.com> wrote: > On Wednesday, September 12, 2012 3:11:42 PM UTC+2, Steven D'Aprano wrote: > > On Wed, 12 Sep 2012 05:48:09 -0700, Libra wrote: > > > > I need to implement a function that returns 1 only if all the values in > > > a list satisfy given constraints (at least one constraint for each > > > element in the list), and zero otherwise. > > > > What are the restrictions on the constraints themselves? > > Could they be arbitrarily complicated? > > "Item 2 must be an even number divisible by 17 and 39 with at least eight > > digits but no greater than four million, unless today is Tuesday, in > > which case it must be equal to six exactly." > > Generally the constraints are quite simple, like the one in my example. > But I can also have 2 or more constraints for each value: > L[0] >= 1 > L[0] <= 5 >
You can use: lambda x: 1 <= x and x <= 5 or lambda x: 1 <= x <= 5 > To complicate a little, what about constraints like: > L[0] + L[2] >= 3 You could rewrite all your constraints as functions on the sequence of values: lambda y: 1 <= y[0] <= 5 lambda y: y[0] + y[2] >= 3 If all of your constraints are linear (like all of the ones you have shown) then you can represent each one as a set of coefficients for a linear projection of the list combined with a threshold value (if this last point doesn't make sense then just ignore it). Oscar
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