Python Program to get all Possible Slices of a String for K Number of Slices

In this article, the user will understand how to get all possible slices of a string for K number of slices in a Python program. Two different examples are depicted in this article. We will employ an iteration approach to accomplish the desired result. In the second example, we will utilize the itertools.combinations approach to obtain the sliced string.

Let's take an example to demonstrate the computation. The following examples are provided for understanding purposes, and we will go through the computation process one by one.

Example 1: Finding all possible slices of a string for K number of slices using the iteration approach.

Algorithm

Step 1: Open Jupyter Notebook in the Anaconda prompt and start writing the code in its cell.

Step 2: Use ‘get_all_slices’ function, it takes the input string (string) and the number of slices ‘(k)’. It will initialize an empty ‘slices [[ ]]’ list to store the results.

Step 3: Function checks, if k > length of the string (n).

Step 4: for i in range(k): iteration-based solution for generating all possible slices of a string.

Step 5: range(k) generates a sequence of numbers from 0 up to k-1.

Step 6: new_slices = []: Initialize an empty list called new_slices in each iteration of the outer loop. This will store the newly generated slices for the current iteration.

Step 7: for slice_list in slices: This is a nested loop it iterates over the existing slices from the previous iteration.

Step 8: remaining_length = len(string) - sum(map(len, slice_list)): Calculates the remaining length of the string after taking the lengths of the existing slices.

Step 9: Uses a map(len, slice_list) to get a list of the lengths of individual slices and gets their sum.

Step 10: Get the remaining length by subtracting this sum from the total length of the string.

Step 11: for j in range(1, remaining_length + 1): it will generate all possible lengths (j) for the new slice. It will start from 1 and reach remaining_length.

Step 12: new_slices.append(slice_list + [string[:j]]): Append a new slice to the new_slices list. It will concatenate the current slice list (slice_list) with a new slice created by slicing the string from 0 up to j.

Step 13:slices = new_slices: After generating all slices for the current iteration, then the slices variable is updated with the new_slices list. This will allow the next iteration to build upon the new slices.

Step 14: Finally, the final slices list will contain all slices of the string for the given number of slices (k).

Step 15: As a result, the function returns the slices list.

Code for sliced string

Example

def get_all_slices_iteration(string, k):
    slices = [[]]
    for i in range(k):
        new_slices = []
        for slice_list in slices:
            remaining_length = len(string) - sum(map(len, slice_list))
            for j in range(1, remaining_length + 1):
                new_slices.append(slice_list + [string[:j]])
        slices = new_slices
    
    return slices

# Example 
input_string = "welcome"
num_slices = 3
result = get_all_slices_iteration(input_string, num_slices)
# Print the result
for slice_list in result:
    print(slice_list)

Viewing The Result - Example 1

This approach will iteratively build slices by extending the existing slices from the previous iteration. It can be calculated the remaining length of the string and will generate all possible lengths for the new slice in each iteration, increasingly constructing all expected slices.

Output

['w', 'w', 'w']
['w', 'w', 'we']
['w', 'w', 'wel']
['w', 'w', 'welc']
['w', 'w', 'welco']
['w', 'we', 'w']
['w', 'we', 'we']
['w', 'we', 'wel']
['w', 'we', 'welc']
['w', 'wel', 'w']
['w', 'wel', 'we']
['w', 'wel', 'wel']
['w', 'welc', 'w']
['w', 'welc', 'we']
['w', 'welco', 'w']
['we', 'w', 'w']
['we', 'w', 'we']
['we', 'w', 'wel']
['we', 'w', 'welc']
['we', 'we', 'w']
['we', 'we', 'we']
['we', 'we', 'wel']
['we', 'wel', 'w']
['we', 'wel', 'we']
['we', 'welc', 'w']
['wel', 'w', 'w']
['wel', 'w', 'we']
['wel', 'w', 'wel']
['wel', 'we', 'w']
['wel', 'we', 'we']
['wel', 'wel', 'w']
['welc', 'w', 'w']
['welc', 'w', 'we']
['welc', 'we', 'w']
['welco', 'w', 'w']

Example 2: Finding all possible slices of a string for K number of slices using ‘itertool.combinational’ approach.

Code Explanation and Design Steps

Step 1: Open Jupyter Notebook in the Anaconda prompt and start writing the code in its cell.

Step 2: Use ‘get_all_slices’ function, it takes the input string (string) and the number of slices ‘(k)’. It will initialize an empty ‘slices []’ list to store the results.

Step 3: The function then checks if k > length of the string (n). If so, it returns an empty slice list.

Step 4: Outer loop will iterate from 1 to k-1 which will be representing the number of characters in the prefix.

Step 5: Inner loop will iterate from 1 to n-1 which will be representing the number of characters in the suffix.

Step 6: From each combination of prefix and suffix lengths, it will sum up to the length of string (n).

Step 7: Extract prefixes and suffixes from the input string.

Step 8: Append them as a list to slices list.

Step 9: Use itertools.combinations function to generate all combinations of indices from 1 to n-1.

Step 10: Iterate over these combinations and create slice lists by dividing the string which will be based on the selected indices.

Step 11: Collect all slice configurations in the slices list, and return it as a final result.

Code For itertool.combinational approach

Example

import itertools

def gt_combinations(string, k):
    slices = []
    for combo in itertools.combinations(range(1, len(string)), k - 1):
        indices = [0] + list(combo) + [len(string)]
        slice_list = [string[indices[i]:indices[i + 1]] for i in range(k)]
        slices.append(slice_list)
    
    return slices

# Example
ist = "welcome"
nt = 3
result = gt_combinations (ist, nt)

# Print the result
for slice_list in result:
    print(slice_list)

Viewing The Result - Example 2

For seeing the result open the loactionfile.html in a browser. Now click the button to find the current location of the user. The coordinates are displayed on the html page.

Output

['w', 'e', 'lcome']
['w', 'el', 'come']
['w', 'elc', 'ome']
['w', 'elco', 'me']
['w', 'elcom', 'e']
['we', 'l', 'come']
['we', 'lc', 'ome']
['we', 'lco', 'me']
['we', 'lcom', 'e']
['wel', 'c', 'ome']
['wel', 'co', 'me']
['wel', 'com', 'e']
['welc', 'o', 'me']
['welc', 'om', 'e']
['welco', 'm', 'e']

In this article, using both approaches achieve the same result but the way of implementation is different. The first approach uses iteration, the second approach uses itertools.combinations function that will generate all combinations of indices for slicing the string. We can choose any approach that suits our requirements or preferences.