Check element exists in array

Question

In PHP there a function called isset() to check if something (like an array index) exists and has a value. How about Python?

I need to use this on arrays because I get \

Answer 1

In Python you might be in for some surprises if you ask for forgiveness in this case.

try-except is not the right paradigm here.

If you accidentally get negative indices your in for a surprise.

Better solution is to provide the test function yourself:

def index_in_array(M, index):
    return index[0] >= 0 and index[1] >= 0 and index[0]< M.shape[0] and index[1] < M.shape[1]