Python – Extract Missing Ranges

Given list of tuples, start range and end range values, extract the ranges that are missing from the list.

Input : test_list = [(7, 2), (15, 19), (38, 50)], strt_val = 5, stop_val = 60
Output : [(5, 7), (2, 60), (2, 15), (19, 60), (19, 38), (50, 60)]
Explanation : Missing element ranges starting from 5 and ending at 50-60 are output as desired.

Input : test_list = [(7, 2), (15, 19), (38, 50)], strt_val = 1, stop_val = 52
Output : [(1, 7), (2, 60), (2, 15), (19, 60), (19, 38), (50, 52)]
Explanation : Similar as above, just ranges are altered.

Method : Using loop
This is brute force method in which this task can be performed. In this, we keep track of start and stop values, and keep adding the missing ranges. At last, its important to check if any range is left less than higher range.

# Python3 code to demonstrate working of
# Extract Missing Ranges
# Using loop

# initializing lists
test_list = [(6, 9), (15, 34), (48, 70)]

# printing original list
print("The original list is : " + str(test_list))

# initializing start val
strt_val = 2

# initializing stop val
stop_val = 100

# Using loop
res = []
for sub in test_list:

    # checking for start range
    if sub[0] > strt_val:
        res.append((strt_val, sub[0]))
        strt_val = sub[1]

    # checking for end range
    if strt_val < stop_val:
        res.append((strt_val, stop_val))

# printing result
print("Missing range tuples : " + str(res))

Output :

The original list is : [(6, 9), (15, 34), (48, 70)]
Missing range tuples : [(2, 6), (9, 100), (9, 15), (34, 100), (34, 48), (70, 100)]