Question

Ok, So I have a 2-d array of data which has the shape(23025, 1000), it’s called ‘allfiles’.

I need to go through the array 50 columns at a time and extract them to a sub-array for manipulation. The problem is when i address the array using the code below, it doesn’t seem to recognize the variables (a and b). the code i have at the moment is shown below.

    q = 50
    a = np.shape(allfiles)[1] # a = 1000
    for i in range(a):
        b = a + q
        data = allfiles[:,a:b]

When i replace the variables with number, i.e…

    data = allfiles[:,30:80]

It seems to work. So, my question is – is there a way i can pass variables to the array index? If not is there a better way i can create a subarray using variables?

I have tried to find this problem on stack overflow with no luck, but i’m sure i’m not the first person to have this trouble?

Cheers guys,
Morgan

Answer 1

You are getting i from the loop but don’t use it.

q = 50

for start in xrange(0, allfiles.shape[1], q):
    data = allfiles[:,start:start+q]
    ...