Sorry to ask so much question at the border between Sage and Python, but I try many attempt before asking.
The following code use list comprehension
A=[[3, 2, 1, 1, 0, 0, 0], [4, 3, -1, 0, -1, 1, 0]]
B=[3,5]
AA=[v[:i] for i in B for v in A]
AA
the result is
[[3, 2, 1], [4, 3, -1], [3, 2, 1, 1, 0], [4, 3, -1, 0, -1]]
but the result I want is [[3, 2, 1],[4, 3, -1, 0, -1]]
that is B[0]
is applied to A[0]
and B[1]
is applied to A[1]
and so on for larger exemple. Is there a way to give some conditions in list comprehension (I would like not to use loop)