How to find the intersection between each pair of LineString in Shapely?

Question

I have a list of sublist which contains the LineString from Shapely such as following:

My_list = [
           [(0, 0), (1, 1), (1,2), (2,2)], 
           [(0, 0), (1, 1), (2,1), (2,2)], 
           [(-1, 0), (1, -1), (-2,1), (2,0)]
          ]

In my list, I have three (in this example they are three, in my case they are thousands) sets which are defined as LineString in Shapely.

Now I like to iteratively find the intersection between each sublist, for example as I said, here I have three LineStrings. Lets call them a1, a2, a3.

a1 = [(0, 0), (1, 1), (1,2), (2,2)]

a2 = [(0, 0), (1, 1), (2,1), (2,2)]

a3 = [(-1, 0), (1, -1), (-2,1), (2,0)]

I want to find the intersection check (and find the intersection as well) between each pair: (a1,a2), (a1,a3), (a2,a1), (a2,a3), (a3,a1), (a3,a2).

Answer 1

Below a function which finds the intersection between 2 lists of iterables:

def find_intersection(list1,list2):
    lst =[]
    for el1 in list1 :
            if any(el1 is el2 for el2 in list2):
                lst.append(el1)
    return lst

you can use it in a loop as I did to return all the possible intersections between all the sublists:

result = []
for index1 in range(0,len(My_list)):
    for index2 in range(0,len(My_list)) :
        if index1 is not index2 :
            inter = find_intersection(My_list[index1],My_list[index2])
            if inter :
                result.append({('a'+str(index1 +1 ),'a'+str(index2 + 1 )): inter})

to make the result readable I made it return a list of dictionaries like : [ { (a1,a2) :inter1 } (a1,a3) :inter2 } ect .. ]

Note that I ignored couples with no intersection in the result list.