How To Replace Multiple Characters in String in Python?

Are you curious to know “How to Replace Multiple Characters in String in Python?“. In this article, we will discuss the available processes to replace multiple characters in a string from the original string that is provided in the program.

Let us try to find out all the possible methods to replace multiple substrings in Python programming language. But before we start replacing multiple characters in a string using some sample Python program, we need to know the basic of our topic.

So, let us start our discussion from the very begging level.

What We Mean By Multiple Characters In A String In Python Program?

In Python programming language, the strings are assumed as objects. And the string concept here is not different from the string concept of other programming languages. A string in Python is a collection of different characters that might be alphabetic or numeric.

st1 = "CodingZap" # String Variable With No Occurance (Normal String)
st2 = "ababababa" # Stirng Variable With Repetitive Occurance
st3 = "aaaaaaaaa" # String Variable With Single Character Multiple Times

Some characters in a string might occur in a repetitive format. Sometimes they occur one after another or might be they occur after another character. This means if any one character is appearing multiple times it will be marked as a string with multiple characters.

Got stuck to understand this code? No worries, you can get all your queries answered by hiring CodingZap experts. You can also hire us if you’re facing any difficulties solving your Python homework.

What Are The Methods To Replace Multiple Characters & Restore Original String?

When we deal with string concepts in any programming language, there is a need to replace multiple characters in a string with other characters. Sometimes, programmers need to do such operations to make similarities among different strings.

So, there is a necessity to learn methods to replace multiple characters in a string in Python programming language. There are five possible methods present for replacing multiple characters in a string & restore the original string. They are the following:

1. Replace Multiple Characters In A String Using replace() Function
2. Replace Multiple Characters In A String Using re.sub() Function
3. Replace Multiple Characters In A String Using translate() & maketrans() Functions
4. Replace Multiple Characters In A String Using List Comprehension Method
5. Replace Multiple Characters In A String Using Dictionary Values

Let us try to know one by one method briefly along with sample examples.

How To Replace Multiple Characters In A String Using replace() Function

Overview Of The Concept:

To replace multiple characters & restore the original string, the best effective method is to use the replace() function. The replace() is one of the built in functions present in the Python programming language. The use of function replaces will remove all the occurrences of a single character in the string.

General Syntax: string-name.replace(“present character”, “replacing character”)

There is also a third parameter or third argument present in the syntax of replace() function. It is completely optional & it helps to know the number of replacements needed for the string in Python. To understand the concept of string in a better way, you can check out our article on “comparing strings in Python” and clear all your doubts.

Code To Understand The Implementation Of replace() Function:

zap = "aaaaaa" # Assigning The String Value
print("Original string: ", zap) # Printing The Original Value Character

one = zap.replace("a", "x") # Replacing 'x' With 'a' Using replace() Function 
print("New string: ", one) # Printing The Replaced Value Character

Steps Of The Program:

1. First, provide the original string as the input string in the Python program. The string data will be printed in the program.
2. Now, the replace() function will be implemented. Provide the character as the first argument that should be changed with another character. And provide the new character as the second argument to the function.
3. The replace() function accepts the arguments & removes all the occurrences of the character along with the new one. Now, the new string data will be printed inside the program.

The output of the program helps to find out if the replacement string is now a new string that is converted. Whatever the original string is, using the replace() function the new string can be developed by removing all the occurrences.

How To Replace Multiple Characters In A String Using re.sub() Function

Overview Of The Concept:

The above method where the replace() function or the regex module is used for replacing multiple occurrences of characters is the superior method. Along with that, there is a method that uses another built in function in the Python program.

It is known as the re.sub() method. The sub-method present there use regular expressions which helps to replace a single character appearing multiple times. Regular expressions are used as a character sequence that creates a search pattern.

General Syntax: re.sub(“present character”, “replacing character”,string-name)

In this method also, there is a need to provide two arguments. One is for the character that will be replaced in the new string. And another character that will be used for the replacement purpose. And the third argument will be the string name itself.

Code To Understand The Implementation Of re.sub() Function:

import re # Importing The Package

zap = "bbbbb" # Assigning The Input String Value
print("Original String: ", zap) # Printing Original Value

one = re.sub("b", "y", zap) # Using The re() Function To Change "b" To "y"
print("New String: ", one) # Printing New Value

Steps Of The Program:

1. Import the necessary “re” module to the program to use all the components of it.
2. Now, declare one empty string & provide some value to it. It will be the original string that will be used in the program.
3. Now, we will use the syntax of the function. We will provide all the arguments needed there. The first two will be the characters & the last one will be the string name.
4. Now, the new string data will print in the program. So, we will get the changes in between them.

Output:

From the output, we can see that the character is now changed in the replaced string. The characters that we have provided in the program are now present in the original string. So, the replacement of the characters is performed correctly.

How To Replace Multiple Characters Using translate() & maketrans() Functions?

Overview Of The Concept:

The translate() & maketrans() function collaboratively helps to remove multiple characters in any string. The maketrans() is used inside of the translate() function. Both of them use the mapping table for replacement purposes.

The translate() & maketrans() functions use the translation table method for making the changes. In simple words, the translation table helps to mark one character to another character in the string. That is the reason, multiple calls can be done for different characters.

General Syntax: string-name.translate(string-name.maketrans(“present character”, “replacing character”))

After implementing the translation table, the translated string comes out with all the replaced characters. In the above example of the syntax, we can see that the implementation of the maketrans() is done inside of the translate() function.

Code To Understand The Implementation Of translate() & maketrans() Functions:

zap = "cccccc" # Assiging The String Value
print("Original String: ", zap) # Printing Original String

one = zap.translate(zap.maketrans("c", "z")) # Using Translate() & Maketrans()
print("New String: ", one) # Printing New String

Steps Of The Program:

1. Declare one string variable & provide some value to it which will be used inside of the program.
2. Now, the original data will be printed in the program to show the difference among the replacement strings.
3. Now, following the above syntax, the translate() & maketrans() functions will be implemented. We should provide the character that should be replaced with another one.
4. Now, the new data will be printed in the program. Hence, we can get the differences.

Output:

How To Replace Multiple Characters Using List Comprehension Method?

Overview Of The Concept:

Another way to replace multiple characters in any string is to use the List Comprehension method. The List Comprehension method is a way that uses some conditions & iterative methods to solve large problems. But the syntax looks very simple & easy.

# Example Of List Comprehension Method
zap = ["C", "C++", "Code", "Java", "Python"] # List With Different Values
one = [x for x in zap if "C" in x] # List Comprehension In The List

The same thing we can implement for this purpose. In the List Comprehension method, we can mark the conditions that will check the presence of one character. And if the character is present, the replacement character will be inserted there. Otherwise, there will be no change in the sequence.

General Syntax: ”.join([‘replacing character’ if char == ‘present character’ else char for char in string-name])

Code To Understand The Use Of List Comprehension Method:

zap = "dddddd" # Assigning The String Value
print("Original String: ", zap) # Printing The Original Value
 
one = ''.join(['w' if char == 'd'else char for char in zap]) # Changing The Value
print("New String: ", one) # Printing The New Value

Steps Of The Program:

1. Declare the string variable along with some values to it & print the data in the console.
2. Now, we should use the above method syntax inside of the program for making the changes in the string. If the character is present, it will be changed. In other case, the else function will be used.
3. Now, the changed data will be printed in the console. Now, we will notice the difference present there.

Output:

The output clearly shows that the replacement of the characters is done completely. Whenever the character appears in the string is now replaced with the provided string value. Hence, the program was executed successfully.

How To Replace Multiple Characters In A String Using Dictionary Values?

Overview Of The Concept:

The Dictionary is a special concept present in Python programs. The Dictionary works with the help of the key value pairs in Python programs. Here, one element is used as a key to identify & another will be the value that will be deployed instead of the key element. This strategy will be used here.

# Examples Of Dictionary Concept
zap = {1: 'Java', 2: 'Python', 3: 'C++'} # Dictionary With Int Key & Char Value
one = {'Java': 1, 'Python': 2, 'C++': 3} # Dictionary With Char Key & Int Value

Here, the key value will be the character that should be replaced in the program. And the value character will be the alphabetic letter that will be used for the replacement purpose. Multiple calls of key value pairs will help to get the target. String in  one of the most used data types in Java, if you’re interested to learn the methods to compare strings in Java you can check out our article.

General Syntax: dictionary-name.get(char, char) for char in string-name

Code To Understand The Use Of Dictionary Values Method:

zap = "eeeeee" # Assigning The String Value
print("Original String: ", zap) # Printing The Original Value
 
one = {'e': 'v'} # Declaring The Dictionary Value
res = ''.join(one.get(char, char) for char in zap) # # Changing The Value

print("New String: ",res) # Printing The New Value

Steps Of The Program:

1. Declare the string value that will be used in the program. Also, the data will be printed in the console.
2. Now, describe one dictionary along with the key & value inside of that. Place the character that will be replaced as the key. And the value will be the replacing character.
3. Now, according to the syntax call the function. We will use the space to join the string value. And the data will be saved in one variable.
4. Now, the new values will be printed in the console. So, we will get the difference in both data.

Output:

From the output, we can see that the string “eeeeee” is replaced with the new string “wwwwww”. Here, in the dictionary, we have marked the character ‘e’ to be replaced with the character ‘w’. The operation is successful.

Conclusion:

As we saw it is very important to know the possible methods to replace multiple characters in a string.

For different questions, according to the need of them, you should use different methods to replace the multiple characters. It is very difficult to figure out which method is most acceptable for different questions. Better, you should know all of them.

It is advisable to clear the basic concept of the Python programming language. All the methods mentioned here use the basic Python concept to replace the elements. So, without knowing the basic things, it will be difficult to understand the complete topic. If you’re interested to know “How to Split a String?” in other programming languages like C++, then we’re here to help you out.