Python Program to Replace All Occurrences of ‘a’ with $ in a String

This Python program replaces all occurrences of the character ‘a’ with ‘$’ in a given string.

Problem Statement

Write a Python program that replaces all occurrences of the letter ‘a’ with a dollar sign (‘$’) in a given string.

Your program should take a string as input and return the modified string where all occurrences of ‘a’ are replaced with ‘$’. The program should preserve the original case of the letters.

Example: Input: “apple banana avocado” Output: “$pple b$n$n$ $voc$do”

Note:

• The input string can contain uppercase and lowercase letters.
• If the input string does not contain any ‘a’ characters, the program should return the original string unchanged.
• The program should handle strings of any length.
• The program should be case-sensitive, meaning that ‘A’ should not be replaced with ‘$’.

You can implement this program using the replace() method in Python, which allows you to replace one substring with another within a string.

Python Program to Replace All Occurrences of ‘a’ with $ in a String

def replace_characters(string):
    replaced_string = string.replace('a', '$')
    return replaced_string

# Example usage
input_string = 'apple banana avocado'
output_string = replace_characters(input_string)
print(output_string)

How it Works

The Python program works by utilizing the replace() method to replace all occurrences of the letter ‘a’ with a dollar sign (‘$’) in the given string. Here’s how it works:

1. The program defines a function called replace_characters that takes a string as input.
2. Inside the function, the replace() method is used on the input string to replace all occurrences of ‘a’ with ‘$’. The modified string is assigned to the variable replaced_string.
3. The modified string replaced_string is then returned as the output of the function.
4. Outside the function, an example input string is provided and assigned to the variable input_string.
5. The replace_characters function is called with input_string as the argument, and the returned value is assigned to the variable output_string.
6. Finally, the modified string output_string is printed to the console.

The replace() method is a built-in string method in Python that takes two arguments: the substring to be replaced and the substring to replace it with. In this case, ‘a’ is specified as the substring to be replaced, and ‘$’ is specified as the substring to replace it with.

The replace() method scans the input string and replaces all occurrences of ‘a’ with ‘$’, creating a new modified string. The original string remains unchanged. The function replace_characters encapsulates this logic and allows for reusability.

Input/ Output