Python: Find the shortest distance from a specified character in a given string

Last update on March 29 2025 13:02:42 (UTC/GMT +8 hours)

23. Shortest Distance for Character

Write a Python program to find the shortest distance from a specified character in a given string. Return the shortest distances through a list and use an itertools component to solve the problem.

Sample Solution:

Python Code:

import itertools as it

def char_shortest_distancer(str1, char1):
    result = [len(str1)] * len(str1)
    prev_char = -len(str1)
    for i in it.chain(range(len(str1)),reversed(range(len(str1)))):
        if str1[i] == char1:
            prev_char = i
        result[i] = min(result[i], abs(i-prev_char))
    return result

str1 = "w3resource"
chr1='r'
print("Original string:",str1,": Specified character:",chr1)
print(char_shortest_distancer(str1,chr1))

str1 = "python exercises"
chr1='e'
print("\nOriginal string:",str1,": Specified character:",chr1)
print(char_shortest_distancer(str1,chr1))


str1 = "JavaScript"
chr1='S'
print("\nOriginal string:",str1,": Specified character:",chr1)
print(char_shortest_distancer(str1,chr1))

Sample Output:

Original string: w3resource : Specified character: r
[2, 1, 0, 1, 2, 2, 1, 0, 1, 2]

Original string: python exercises : Specified character: e
[7, 6, 5, 4, 3, 2, 1, 0, 1, 0, 1, 2, 2, 1, 0, 1]

Original string: JavaScript : Specified character: S
[4, 3, 2, 1, 0, 1, 2, 3, 4, 5]

For more Practice: Solve these Related Problems:

• Write a Python program to compute the shortest distance from a specified character to every occurrence in a string using itertools and list comprehensions.
• Write a Python program to generate a list of distances from a given character to all positions in a string and then return the minimum distance.
• Write a Python program to iterate through a string and compute the distance to the nearest occurrence of a specified character using a sliding window approach.
• Write a Python program to use itertools to group indices of a given character in a string and then calculate the shortest gap between consecutive occurrences.

Python Code Editor:

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Next: Write a Python program to find the maximum length of a substring in a given string where all the characters of the substring are same. Use itertools module to solve the problem.