Python: String Compression

The idea of string compression is as follows: AAAB > A3B1. That is, if we’re given 3 A’s and 1 B, the output should be A3B1.

If we go by this logic, for input of AAABaaaaAA, we should get A5B1a4. This can be achieved by the code given below:

# string compression problem
# AAAB > A3B1

def compress_string(s):
    
    temp = {}
    for letter in s:
        if letter in temp:
            temp[letter] += 1
        else:
            temp[letter] = 1
            
    compressed_string = ''
    
    for letter in temp:
        compressed_string += letter + str(temp[letter])
        
    return compressed_string

compress_string('AAABaaaaAA') #Output: A5B1a4

The code starts with a temp dictionary. It then looks at each letter in the input string and counts it using temp.

Next it simply concatenates letter (the actual character) and str(temp[letter]) (the count of that character) in a variable called compressed_String and prints it.