Python Practice › String Programs › Program 8

Longest run of a repeated character

MediumString Programs · 8 of 106

Write a Python program to find the character that repeats most times in a row (consecutively) in a string.

Input

"aabbbbcccdd"

Output

b 4

Approach

Walk through the string, counting the current run, and remember the longest one.

Solution

Python

text = "aabbbbcccdd"best_char, best_len = text[0], 1run_len = 1for i in range(1, len(text)):    if text[i] == text[i - 1]:        run_len += 1    else:        run_len = 1    if run_len > best_len:        best_char, best_len = text[i], run_lenprint(best_char, best_len)

Output

b 4

Line by line

Lines 5-8

The run grows while characters repeat and resets on a change.

Lines 9-10

Save the run if it is the longest so far.

Tip

itertools.groupby(text) groups consecutive equal characters for you.

Learn the concept

New to this topic? Read the lesson, then come back.

Strings & Methods lesson → String Formatting & f-strings lesson →

More string programs

#9EasyString length with a loop #10MediumReplace the second occurrence of each character #11EasySwap the first and last characters #12EasySwap first and last letters of each word

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