Question

I hoping someone can help me with a problem I’m stuck(again) with.

if i have coordinates:

 x = array[0,1,2,3,4,3,2,3,-2,-4,-7,2,2]
 y = array[0,1,2,3,4,5,6,7,8,9,10,11,12]

and with help in Categorizing the list of array in python, i could make:

x = [(0, 1, 2, 3, 4), (4, 3, 2), (2, 3), (3, -2, -4, -7), (-7, 2), (2, 2)]

The question is, how should i made y like this:

y = [(0,1,2,3,4),(4,5,6),(6,7),(7,8,9,10),(10,11),(11,12)]

since, x and y is actually coordinates and they bounded each other.

i have tried to use loop function, and i realize the code is still wrong

se = []
for i in range(len(z)):
        k = z[i]
        for i in range(len(k)):
                se.append(y[i])

best regards,

Glenn

Answer 1

The following does what you want:

x = [(0, 1, 2, 3, 4), (4, 3, 2), (2, 3), (3, -2, -4, -7), (-7, 2), (2, 2)]
y = [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12]

s = map(len, x)
s = [0] + [sum(s[:i])-i for i in range(1, len(s))] + [len(y)]
y = [tuple(y[a:b+1]) for a, b in zip(s, s[1:])]

Result:

>>> y
[(0, 1, 2, 3, 4), (4, 5, 6), (6, 7), (7, 8, 9, 10), (10, 11), (11, 12)]

This basically constructs a list of positions where y will be split. We figure this out using the length of each tuple in x, but it gets a little tricky because the last element of a set is included as the next element in the following set.

Here is one of the intermediate values which may help to clarify how this works:

>>> zip(s, s[1:])
[(0, 4), (4, 6), (6, 7), (7, 10), (10, 11), (11, 13)]

We use this to construct the new y like this:

[(0, 4), (4,  6), (6,  7), (7, 10), (10, 11), (11, 13)]
   \ |     \   \    \_  \
   | |      \  |      \  |
[y[0:4+1], y[4:6+1], y[6:7+1], ...]