Coordinates of item on NumPy array

Question

I have a NumPy array:

[[  0.   1.   2.   3.   4.]
 [  7.   8.   9.  10.   4.]
 [ 14.  15.  16.  17.   4.]
 [  1.  20.  21.  22.  23.]
 [ 27.  28.   1.  20.  29.]         


        

Answer 1

a = numpy.array([[  0.,  1.,  2.,  3.,  4.],
                 [  7.,  8.,  9., 10.,  4.],
                 [ 14., 15., 16., 17.,  4.],
                 [  1., 20., 21., 22., 23.],
                 [ 27., 28.,  1., 20., 29.]])
print numpy.argwhere(a == 4.)

prints

[[0 4]
 [1 4]
 [2 4]]

The usual caveats for floating point comparisons apply.

Answer 2

If a is your array, then you could use:

ii = np.nonzero(a == 4)

or

ii = np.where(a == 4)

If you really want a tuple, you can convert from the tuple of arrays to the tuple of tuples, but the return value from the numpy functions is convient for then doing other operations on your array.

Conversion to a tuple for the OP's specification:

tuple(zip(*ii))