Merge elements in list based on given indices

Question

I want to merge element in the list based on given start and stop index of tuple (non-overlap for tuple). I\'ll leave the indices that don\'t mention as it is. This is my ex

Answer 1

Short "trick" with reversed merge list:

ls = ['1', '2', '3', '4', '5', '6', '7']
merge = [(1, 3), (5, 7)]

for t in merge[::-1]:
    merged = ''.join(ls[t[0]:t[1]])  # merging values within a range
    ls[t[0]:t[1]] = [merged]         # slice replacement

print(ls)

The output:

['1', '23', '4', '5', '67']

Answer 2

For the fun of it, because I've been learning Haskell, a recursive solution:

def recursive(ls, merge):
    if merge == []:
        return ls
    else:
        x, xs = merge[0], merge[1:]
        return ls[:x[0]] + [''.join(ls[x[0]:x[1]])] + recursive(ls, xs)[x[1]:]

Only works if there are no overlapping intervals, however.

Answer 3

A quick-and-dirty solution would be:

ls = ['1', '2', '3', '4', '5', '6', '7']
merge = [(1, 3), (5, 7)]

result = []
index = 0

for start, end in merge:
    result += ls[index:start]
    result.append("".join(ls[start:end]))
    index = end

print result # ['1', '23', '4', '5', '67']