creating a function for for-loop across specific set of ranges in python

Question

How can you loop across multiple different ranges. for example say i want to run a for loop for specific set of ranges

1 to 2, 4 to 6 and 10 to 13,

I don't know the exact final number so maybe a function might be useful.

The standard method of

for i in range(1,2) + range (4,6) + range (10,13)

I should have this

[1,4,5,6,10,11,13]

My question is, this is not so efficient, if i don't know the total number of ranges am covering, and I can't even create this as a function without so many parameters.

so if i want to have something like this

for i in range(a,b) + range (c,d) + range (e,f), ..... 

but as a simple function Can someone help with an efficient way of doing this ?

Answer 1

Simple, though most likely the least efficient solution is to use a nested for loop,

def multi_range_loop(ranges):

    all_values = []
    for rg in ranges:
        for i in range(rg[0], rg[1]):
            all_values.append(i)
    print(all_values)

my_ranges = [[1,3],[4,7],[10,14]]
multi_range_loop(my_ranges)

Answer 2

You can chain the ranges with itertools:

from itertools import chain

total_range = chain(range(1,2), range(4,6), range(10,13))

print(list(total_range))
#[1, 4, 5, 10, 11, 12]

Here is another solution with a function that returns a generator:

def total_range(lst):
    return (i for tup in lst for i in range(tup[0], tup[1]))

list_of_ranges = [(1,2), (4,6), (10,13)]
print(list(total_range(list_of_ranges)))