# Python function to quickly compare values of a matrix?

## Question:

I’m sorry to be asking a basic question, but I’ve been working on a signal analysis project for which we need to assign a variable based on which quadrant a set of values (n-dimensional vector) lies in. As a biomedical engineer, I’ve been struggling to maybe find a more efficient or "prettier" solution. Currently, the way in which I’m working for a 3 dimensional vector is by doing multiple comparissons:

``````if (ondas>0)&(ondas>0)&(ondas>0):
note=1
elif (ondas>0)&(ondas>0)&(ondas<0):
note=2
elif (ondas>0)&(ondas<0)&(ondas<0):
note=3
elif (ondas<0)&(ondas<0)&(ondas<0):
note=4
elif (ondas<0)&(ondas>0)&(ondas<0):
note=5
elif (ondas<0)&(ondas<0)&(ondas>0):
note=6
elif (ondas<0)&(ondas>0)&(ondas>0):
note=7
elif (ondas>0)&(ondas<0)&(ondas>0):
note=8
else:
note=0
``````

Where `ondas` is my array with 3 values. This code works sufficiently well, but I wonder if there’s another way to tackle the problem. I’ve been working well enough with this solution, but I’m open to feedback on the issue.

There are many different ways to approach this problem. The easiest is probably to create a boolean value for each axis and store the respective quadrant for each configuration in a dictionary. This is basically the same as what you did, only shorter and clearer:

``````axis_to_quad = {(0, 0, 0): 1,
(0, 0, 1): 2,
(0, 1, 1): 3,
(1, 1, 1): 4,
(1, 0, 1): 5,
(1, 1, 0): 6,
(1, 0, 0): 7,
(0, 1, 0): 8}

note = axis_to_quad[(ondas < 0, ondas < 0, ondas < 0)]
``````

Not really changing your logic, but replacing `&` with `and`, getting rid of lots of parens, adding some whitespace, and using a conditional expression.

``````note = 1 if ondas > 0 and ondas > 0 and ondas > 0 else
2 if ondas > 0 and ondas > 0 and ondas < 0 else
3 if ondas > 0 and ondas < 0 and ondas < 0 else
4 if ondas < 0 and ondas < 0 and ondas < 0 else
5 if ondas < 0 and ondas > 0 and ondas < 0 else
6 if ondas < 0 and ondas < 0 and ondas > 0 else
7 if ondas < 0 and ondas > 0 and ondas > 0 else
8 if ondas > 0 and ondas < 0 and ondas > 0 else
9
``````
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