Python – Cumulative List Split

Sometimes, while working with String lists, we can have a problem in which we need to perform the task of split and return all the split instances of list in cumulative way. This kind of problem can occur in many domains in which data is involved. Lets discuss certain ways in which this task can be performed.
Method #1 : Using loop
This is brute force way in which this task is performed. In this, we test for the list and append the list when ever we encounter the split character.

Python3

# Python3 code to demonstrate working of
# Cumulative List Split
# Using loop

# initializing list
test_list = ['gfg-is-all-best']

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

# initializing Split char
spl_char = "-"

# Cumulative List Split
# Using loop
res = []
for sub in test_list:
    for idx in range(len(sub)):
        if sub[idx] == spl_char:
            res.append([ sub[:idx] ])
    res.append([ sub ])

# printing result
print("The Cumulative List Splits : " + str(res))

Output

The original list is : ['gfg-is-all-best']
The Cumulative List Splits : [['gfg'], ['gfg-is'], ['gfg-is-all'], ['gfg-is-all-best']]

Method #2 : Using accumulate() + join()
This is one-liner approach to this problem. In this, we perform the task of cutting into cumulative using accumulate and join() is used to construct the resultant List of lists.

Python3

# Python3 code to demonstrate working of
# Cumulative List Split
# Using accumulate() + join()
from itertools import accumulate

# initializing list
test_list = ['gfg-is-all-best']

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

# initializing Split char
spl_char = "-"

# Cumulative List Split
# Using accumulate() + join()
temp = test_list[0].split(spl_char)
res = list(accumulate(temp, lambda x, y: spl_char.join([x, y])))

# printing result
print("The Cumulative List Splits : " + str(res))

Output

The original list is : ['gfg-is-all-best']
The Cumulative List Splits : ['gfg', 'gfg-is', 'gfg-is-all', 'gfg-is-all-best']