Python – Incremental Size Chunks from Strings

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Given a String, split it into incremental sizes consecutive list.

Input : test_str = ‘geekforzambiatek is best’
Output : [‘g’, ‘ee’, ‘kfo’, ‘rgee’, ‘ks is’, ‘ best’]
Explanation : Characters size increasing in list.

Input : test_str = ‘geekforzambiatek’
Output : [‘g’, ‘ee’, ‘kfo’, ‘rgee’, ‘ks’]
Explanation : Characters size increasing in list.

Method #1 : Using loop + slicing

In this, we perform task of getting chunks using string slicing and keep on increasing chunk size during iteration.

Python3

# Python3 code to demonstrate working of 
# Incremental Size Chunks from Strings
# Using loop + slicing
 
# initializing string
test_str = 'geekforzambiatek is best forzambiatek'
 
# printing original string
print("The original string is : " + str(test_str))
 
res = []
idx = 1
while True:
    if len(test_str) > idx:
         
        # chunking
        res.append(test_str[0 : idx])
        test_str = test_str[idx:]
        idx += 1
    else:
        res.append(test_str)
        break
     
# printing result 
print("The Incremental sized Chunks : " + str(res)) 

Output

The original string is : geekforzambiatek is best forzambiatek
The Incremental sized Chunks : ['g', 'ee', 'kfo', 'rgee', 'ks is', ' best ', 'for gee', 'ks']

Time Complexity: O(n)
Auxiliary Space: O(n)

Method #2 : Using generator + slicing

In this, we perform slicing as in above method, difference is that chunks are rendered using generator expression, each chunk yields at runtime in loop.

Python3

# Python3 code to demonstrate working of 
# Incremental Size Chunks from Strings
# Using generator + slicing 
 
# generator function 
def gen_fnc(test_str):
    strt = 0
    stp = 1
    while test_str[strt : strt + stp]:
         
        # return chunks runtime while looping
        yield test_str[strt : strt + stp]
        strt += stp
        stp += 1
 
# initializing string
test_str = 'geekforzambiatek is best forzambiatek'
 
# printing original string
print("The original string is : " + str(test_str))
 
# calling fnc.
res = list(gen_fnc(test_str))
     
# printing result 
print("The Incremental sized Chunks : " + str(res)) 

Output

The original string is : geekforzambiatek is best forzambiatek
The Incremental sized Chunks : ['g', 'ee', 'kfo', 'rgee', 'ks is', ' best ', 'for gee', 'ks']

Time Complexity: O(n)
Space Complexity: O(n)

Method 3: Using recursion.

Python3

# Python3 code to demonstrate working of 
# Incremental Size Chunks from Strings
# Using recursion
 
# recursive function to generate chunks
def recursive_fnc(test_str, res, strt=0, stp=1):
    if not test_str[strt:strt+stp]:
        return res
    else:
        res.append(test_str[strt:strt+stp])
        return recursive_fnc(test_str, res, strt+stp, stp+1)
 
# initializing string
test_str = 'geekforzambiatek is best forzambiatek'
 
# printing original string
print("The original string is : " + str(test_str))
 
# calling recursive function to generate chunks
res = recursive_fnc(test_str, [])
 
# printing result 
print("The Incremental sized Chunks : " + str(res))

Output

The original string is : geekforzambiatek is best forzambiatek
The Incremental sized Chunks : ['g', 'ee', 'kfo', 'rgee', 'ks is', ' best ', 'for gee', 'ks']

The time complexity of this approach is also O(n^2), where n is the length of the input string.
The space complexity is O(n), as the function generates chunks one at a time and stores them in a list.