Numpy merging arrays

Question

I have two arrays

 a = np.array[1,18,3,13,6,45,45]
 b= np.array [8,13,6,45,45]

after doing some matching exercises I have a list, such as:

[3,1,4]

first and second number of the list are zero based. the third number is not. the list stands for

• start position of first array

• start position of second array

• how many numbers rows to retrieve

so for this example the result would be

13, 13 
6,6
45,45
45,45

Both starting points of the array and then get 4 rows after that.

How can I merge my two arrays using my matchlist?

EDIT This is the matchlist that I am using:

matchlist2 = []

matchlist2.append([3,1,4])
matchlist2.append([9,7,731])
matchlist2.append([766,762,19])
matchlist2.append([800,796,57])
matchlist2.append([867,862,88])
matchlist2.append([960,955,468])
matchlist2.append([1432,1427,65])
matchlist2.append([1523,1518,341])
matchlist2.append([1873,1868,32])
matchlist2.append([1923,1916,82])
matchlist2.append([2011,2004,699])
matchlist2.append([2716,2707,902])
matchlist2.append([3628,3617,247])
matchlist2.append([3923,391,378])
matchlist2.append([4306,4292,5])

Answer 1

This is what you need:

a = np.array([1,18,3,13,6,45,45])
b = np.array([8,13,6,45,45])

look = [3,1,4]
first, second, step = look
c = np.array(zip(a[first:first+step],b[second:second+step]))
c
#[[13 13 
# [ 6  6
# [45 45
# [45 45]]

Answer 2

I would do it something like this:

result = np.array([[[a[ind[0]],b[ind[1]]] for ind in zip(range(ml[0],ml[0]+ml[2]),range(ml[1],ml[1]+ml[2]))] for ml in matchlist2])

Edit: Divakar's solution is actually much more elegant. If you just zip it up you'd get what you need.

result = [list(zip(a[l[0]:l[0]+l[2]],b[l[1]:l[1]+l[2]])) for l in matchlist2]