Search numpy array inside numpy array
To get the same behavior as
in for lists, you could do something like this:
any(np.all(row == m2) for row in m1)
That does the loop over rows in python, which isnt ideal, but it should work.
To understand whats going on with the numpy
in, heres a description of the semantics of
in from Robert Kern on the numpy mailing list:
It dates back to Numerics semantics for bool(some_array), which would
be True if any of the elements were nonzero. Just like any other
iterable container in Python,
x in ywill essentially do
for row in y: if x == row: return True return False
Iterate along the first axis of y and compare by boolean equality. In
Numeric/numpys case, this comparison is broadcasted. So thats why
[3,6,4] works, because there is one row where 3 is in the first
column. [4,2,345] doesnt work because the 4 and the 2 are not in
Probably, this should be considered a mistake during the transition to
numpys semantics of having bool(some_array) raise an exception.
scalar in arrayshould probably work as-is for an ND array, but
there are several different possible semantics for
array in array
that should be explicitly spelled out, much like bool(some_array).