Pineapples - 1 year ago 62

Python Question

How do I check if there is an element in an array where both axes

`[X, Y]`

`[drawx, drawy]`

I have a

`#format: [X, Y]`

wallxy = numpy.array([[0,1],[3,2],[4,6]])

and

`#attached to a counter that increases value each loop`

drawx = 3

drawy = 2

I'm using the array as a set of positions

`[[0,1],[3,2],[4,6]]`

`[drawx, drawy]`

`drawx = 4`

`drawy = 6`

`drawx = 3`

`drawy = 2`

`drawx = 4`

`drawy = 2`

`drawx = 2`

`drawy = 1`

Answer Source

`==`

will broadcast the comparison, so

```
wallxy = numpy.array([[0, 1],[3, 2][4, 6]])
z0 = numpy.array([3,2])
z1 = numpy.array([2,3])
(z0==wallxy).all(1).any() # True
(z1==wallxy).all(1).any() # False
```

Which is, I think, what you're looking for.

Printing out the intermediate steps will be useful to understanding and working out similar tasks:

```
z0 == wallxy # checks which elements match
# array([[False, False],
# [ True, True],
# [False, False]], dtype=bool)
(z0==wallxy).all(1) # checks whether all elements of axis 1 match
# array([False, True, False], dtype=bool)
(z0==wallxy).all(1).any() # checks whether any axis 1 matches z0
# True
```

If instead you used `z0 = numpy.array([2,3])`

, then everything would be `False`

.