Python Program to Replace all Occurrences of 'a' with $ in a String

When it is required to replace all the occurrences of 'a' with a character such as '$' in a string, Python provides multiple approaches. You can iterate through the string manually, use the built-in replace() method, or use string translation methods.

Method 1: Using Manual Iteration

This approach iterates through each character and builds a new string ?

my_str = "Jane Will Rob Harry Fanch Dave Nancy"

changed_str = ''

for char in range(0, len(my_str)):
    if(my_str[char] == 'a'):
        changed_str += '$'
    else:
        changed_str += my_str[char]

print("The original string is :")
print(my_str)
print("The modified string is : ")
print(changed_str)

The original string is :
Jane Will Rob Harry Fanch Dave Nancy
The modified string is : 
J$ne Will Rob H$rry F$nch D$ve N$ncy

Method 2: Using replace() Method

The built-in replace() method is the most straightforward approach ?

my_str = "Jane Will Rob Harry Fanch Dave Nancy"

changed_str = my_str.replace('a', '$')

print("The original string is :")
print(my_str)
print("The modified string is : ")
print(changed_str)

The original string is :
Jane Will Rob Harry Fanch Dave Nancy
The modified string is : 
J$ne Will Rob H$rry F$nch D$ve N$ncy

Method 3: Using List Comprehension

A more Pythonic approach using list comprehension and join() ?

my_str = "Jane Will Rob Harry Fanch Dave Nancy"

changed_str = ''.join(['$' if char == 'a' else char for char in my_str])

print("The original string is :")
print(my_str)
print("The modified string is : ")
print(changed_str)

The original string is :
Jane Will Rob Harry Fanch Dave Nancy
The modified string is : 
J$ne Will Rob H$rry F$nch D$ve N$ncy

Comparison

Conclusion

The replace() method is the most efficient and readable approach for simple character replacements. Use list comprehension when you need more complex replacement logic, and manual iteration for educational purposes or when you need fine-grained control.