- Blog Categories
- Software Development Projects and Ideas
- 12 Computer Science Project Ideas
- 28 Beginner Software Projects
- Top 10 Engineering Project Ideas
- Top 10 Easy Final Year Projects
- Top 10 Mini Projects for Engineers
- 25 Best Django Project Ideas
- Top 20 MERN Stack Project Ideas
- Top 12 Real Time Projects
- Top 6 Major CSE Projects
- 12 Robotics Projects for All Levels
- Java Programming Concepts
- Abstract Class in Java and Methods
- Constructor Overloading in Java
- StringBuffer vs StringBuilder
- Java Identifiers: Syntax & Examples
- Types of Variables in Java Explained
- Composition in Java: Examples
- Append in Java: Implementation
- Loose Coupling vs Tight Coupling
- Integrity Constraints in DBMS
- Different Types of Operators Explained
- Career and Interview Preparation in IT
- Top 14 IT Courses for Jobs
- Top 20 Highest Paying Languages
- 23 Top CS Interview Q&A
- Best IT Jobs without Coding
- Software Engineer Salary in India
- 44 Agile Methodology Interview Q&A
- 10 Software Engineering Challenges
- Top 15 Tech's Daily Life Impact
- 10 Best Backends for React
- Cloud Computing Reference Models
- Web Development and Security
- Find Installed NPM Version
- Install Specific NPM Package Version
- Make API Calls in Angular
- Install Bootstrap in Angular
- Use Axios in React: Guide
- StrictMode in React: Usage
- 75 Cyber Security Research Topics
- Top 7 Languages for Ethical Hacking
- Top 20 Docker Commands
- Advantages of OOP
- Data Science Projects and Applications
- 42 Python Project Ideas for Beginners
- 13 Data Science Project Ideas
- 13 Data Structure Project Ideas
- 12 Real-World Python Applications
- Python Banking Project
- Data Science Course Eligibility
- Association Rule Mining Overview
- Cluster Analysis in Data Mining
- Classification in Data Mining
- KDD Process in Data Mining
- Data Structures and Algorithms
- Binary Tree Types Explained
- Binary Search Algorithm
- Sorting in Data Structure
- Binary Tree in Data Structure
- Binary Tree vs Binary Search Tree
- Recursion in Data Structure
- Data Structure Search Methods: Explained
- Binary Tree Interview Q&A
- Linear vs Binary Search
- Priority Queue Overview
- Python Programming and Tools
- Top 30 Python Pattern Programs
- List vs Tuple
- Python Free Online Course
- Method Overriding in Python
- Top 21 Python Developer Skills
- Reverse a Number in Python
- Switch Case Functions in Python
- Info Retrieval System Overview
- Reverse a Number in Python
- Real-World Python Applications
- Data Science Careers and Comparisons
- Data Analyst Salary in India
- Data Scientist Salary in India
- Free Excel Certification Course
- Actuary Salary in India
- Data Analyst Interview Guide
- Pandas Interview Guide
- Tableau Filters Explained
- Data Mining Techniques Overview
- Data Analytics Lifecycle Phases
- Data Science Vs Analytics Comparison
- Artificial Intelligence and Machine Learning Projects
- Exciting IoT Project Ideas
- 16 Exciting AI Project Ideas
- 45+ Interesting ML Project Ideas
- Exciting Deep Learning Projects
- 12 Intriguing Linear Regression Projects
- 13 Neural Network Projects
- 5 Exciting Image Processing Projects
- Top 8 Thrilling AWS Projects
- 12 Engaging AI Projects in Python
- NLP Projects for Beginners
- Concepts and Algorithms in AIML
- Basic CNN Architecture Explained
- 6 Types of Regression Models
- Data Preprocessing Steps
- Bagging vs Boosting in ML
- Multinomial Naive Bayes Overview
- Gini Index for Decision Trees
- Bayesian Network Example
- Bayes Theorem Guide
- Top 10 Dimensionality Reduction Techniques
- Neural Network Step-by-Step Guide
- Technical Guides and Comparisons
- Make a Chatbot in Python
- Compute Square Roots in Python
- Permutation vs Combination
- Image Segmentation Techniques
- Generative AI vs Traditional AI
- AI vs Human Intelligence
- Random Forest vs Decision Tree
- Neural Network Overview
- Perceptron Learning Algorithm
- Selection Sort Algorithm
- Career and Practical Applications in AIML
- AI Salary in India Overview
- Biological Neural Network Basics
- Top 10 AI Challenges
- Production System in AI
- Top 8 Raspberry Pi Alternatives
- Top 8 Open Source Projects
- 14 Raspberry Pi Project Ideas
- 15 MATLAB Project Ideas
- Top 10 Python NLP Libraries
- Naive Bayes Explained
- Digital Marketing Projects and Strategies
- 10 Best Digital Marketing Projects
- 17 Fun Social Media Projects
- Top 6 SEO Project Ideas
- Digital Marketing Case Studies
- Coca-Cola Marketing Strategy
- Nestle Marketing Strategy Analysis
- Zomato Marketing Strategy
- Monetize Instagram Guide
- Become a Successful Instagram Influencer
- 8 Best Lead Generation Techniques
- Digital Marketing Careers and Salaries
- Digital Marketing Salary in India
- Top 10 Highest Paying Marketing Jobs
- Highest Paying Digital Marketing Jobs
- SEO Salary in India
- Brand Manager Salary in India
- Content Writer Salary Guide
- Digital Marketing Executive Roles
- Career in Digital Marketing Guide
- Future of Digital Marketing
- MBA in Digital Marketing Overview
- Digital Marketing Techniques and Channels
- 9 Types of Digital Marketing Channels
- Top 10 Benefits of Marketing Branding
- 100 Best YouTube Channel Ideas
- YouTube Earnings in India
- 7 Reasons to Study Digital Marketing
- Top 10 Digital Marketing Objectives
- 10 Best Digital Marketing Blogs
- Top 5 Industries Using Digital Marketing
- Growth of Digital Marketing in India
- Top Career Options in Marketing
- Interview Preparation and Skills
- 73 Google Analytics Interview Q&A
- 56 Social Media Marketing Q&A
- 78 Google AdWords Interview Q&A
- Top 133 SEO Interview Q&A
- 27+ Digital Marketing Q&A
- Digital Marketing Free Course
- Top 9 Skills for PPC Analysts
- Movies with Successful Social Media Campaigns
- Marketing Communication Steps
- Top 10 Reasons to Be an Affiliate Marketer
- Career Options and Paths
- Top 25 Highest Paying Jobs India
- Top 25 Highest Paying Jobs World
- Top 10 Highest Paid Commerce Job
- Career Options After 12th Arts
- Top 7 Commerce Courses Without Maths
- Top 7 Career Options After PCB
- Best Career Options for Commerce
- Career Options After 12th CS
- Top 10 Career Options After 10th
- 8 Best Career Options After BA
- Projects and Academic Pursuits
- 17 Exciting Final Year Projects
- Top 12 Commerce Project Topics
- Top 13 BCA Project Ideas
- Career Options After 12th Science
- Top 15 CS Jobs in India
- 12 Best Career Options After M.Com
- 9 Best Career Options After B.Sc
- 7 Best Career Options After BCA
- 22 Best Career Options After MCA
- 16 Top Career Options After CE
- Courses and Certifications
- 10 Best Job-Oriented Courses
- Best Online Computer Courses
- Top 15 Trending Online Courses
- Top 19 High Salary Certificate Courses
- 21 Best Programming Courses for Jobs
- What is SGPA? Convert to CGPA
- GPA to Percentage Calculator
- Highest Salary Engineering Stream
- 15 Top Career Options After Engineering
- 6 Top Career Options After BBA
- Job Market and Interview Preparation
- Why Should You Be Hired: 5 Answers
- Top 10 Future Career Options
- Top 15 Highest Paid IT Jobs India
- 5 Common Guesstimate Interview Q&A
- Average CEO Salary: Top Paid CEOs
- Career Options in Political Science
- Top 15 Highest Paying Non-IT Jobs
- Cover Letter Examples for Jobs
- Top 5 Highest Paying Freelance Jobs
- Top 10 Highest Paying Companies India
- Career Options and Paths After MBA
- 20 Best Careers After B.Com
- Career Options After MBA Marketing
- Top 14 Careers After MBA In HR
- Top 10 Highest Paying HR Jobs India
- How to Become an Investment Banker
- Career Options After MBA - High Paying
- Scope of MBA in Operations Management
- Best MBA for Working Professionals India
- MBA After BA - Is It Right For You?
- Best Online MBA Courses India
- MBA Project Ideas and Topics
- 11 Exciting MBA HR Project Ideas
- Top 15 MBA Project Ideas
- 18 Exciting MBA Marketing Projects
- MBA Project Ideas: Consumer Behavior
- What is Brand Management?
- What is Holistic Marketing?
- What is Green Marketing?
- Intro to Organizational Behavior Model
- Tech Skills Every MBA Should Learn
- Most Demanding Short Term Courses MBA
- MBA Salary, Resume, and Skills
- MBA Salary in India
- HR Salary in India
- Investment Banker Salary India
- MBA Resume Samples
- Sample SOP for MBA
- Sample SOP for Internship
- 7 Ways MBA Helps Your Career
- Must-have Skills in Sales Career
- 8 Skills MBA Helps You Improve
- Top 20+ SAP FICO Interview Q&A
- MBA Specializations and Comparative Guides
- Why MBA After B.Tech? 5 Reasons
- How to Answer 'Why MBA After Engineering?'
- Why MBA in Finance
- MBA After BSc: 10 Reasons
- Which MBA Specialization to choose?
- Top 10 MBA Specializations
- MBA vs Masters: Which to Choose?
- Benefits of MBA After CA
- 5 Steps to Management Consultant
- 37 Must-Read HR Interview Q&A
- Fundamentals and Theories of Management
- What is Management? Objectives & Functions
- Nature and Scope of Management
- Decision Making in Management
- Management Process: Definition & Functions
- Importance of Management
- What are Motivation Theories?
- Tools of Financial Statement Analysis
- Negotiation Skills: Definition & Benefits
- Career Development in HRM
- Top 20 Must-Have HRM Policies
- Project and Supply Chain Management
- Top 20 Project Management Case Studies
- 10 Innovative Supply Chain Projects
- Latest Management Project Topics
- 10 Project Management Project Ideas
- 6 Types of Supply Chain Models
- Top 10 Advantages of SCM
- Top 10 Supply Chain Books
- What is Project Description?
- Top 10 Project Management Companies
- Best Project Management Courses Online
- Salaries and Career Paths in Management
- Project Manager Salary in India
- Average Product Manager Salary India
- Supply Chain Management Salary India
- Salary After BBA in India
- PGDM Salary in India
- Top 7 Career Options in Management
- CSPO Certification Cost
- Why Choose Product Management?
- Product Management in Pharma
- Product Design in Operations Management
- Industry-Specific Management and Case Studies
- Amazon Business Case Study
- Service Delivery Manager Job
- Product Management Examples
- Product Management in Automobiles
- Product Management in Banking
- Sample SOP for Business Management
- Video Game Design Components
- Top 5 Business Courses India
- Free Management Online Course
- SCM Interview Q&A
- Fundamentals and Types of Law
- Acceptance in Contract Law
- Offer in Contract Law
- 9 Types of Evidence
- Types of Law in India
- Introduction to Contract Law
- Negotiable Instrument Act
- Corporate Tax Basics
- Intellectual Property Law
- Workmen Compensation Explained
- Lawyer vs Advocate Difference
- Law Education and Courses
- LLM Subjects & Syllabus
- Corporate Law Subjects
- LLM Course Duration
- Top 10 Online LLM Courses
- Online LLM Degree
- Step-by-Step Guide to Studying Law
- Top 5 Law Books to Read
- Why Legal Studies?
- Pursuing a Career in Law
- How to Become Lawyer in India
- Career Options and Salaries in Law
- Career Options in Law India
- Corporate Lawyer Salary India
- How To Become a Corporate Lawyer
- Career in Law: Starting, Salary
- Career Opportunities: Corporate Law
- Business Lawyer: Role & Salary Info
- Average Lawyer Salary India
- Top Career Options for Lawyers
- Types of Lawyers in India
- Steps to Become SC Lawyer in India
- Tutorials
- C Tutorials
- Recursion in C: Fibonacci Series
- Checking String Palindromes in C
- Prime Number Program in C
- Implementing Square Root in C
- Matrix Multiplication in C
- Understanding Double Data Type
- Factorial of a Number in C
- Structure of a C Program
- Building a Calculator Program in C
- Compiling C Programs on Linux
- Java Tutorials
- Handling String Input in Java
- Determining Even and Odd Numbers
- Prime Number Checker
- Sorting a String
- User-Defined Exceptions
- Understanding the Thread Life Cycle
- Swapping Two Numbers
- Using Final Classes
- Area of a Triangle
- Skills
- Software Engineering
- JavaScript
- Data Structure
- React.js
- Core Java
- Node.js
- Blockchain
- SQL
- Full stack development
- Devops
- NFT
- BigData
- Cyber Security
- Cloud Computing
- Database Design with MySQL
- Cryptocurrency
- Python
- Digital Marketings
- Advertising
- Influencer Marketing
- Search Engine Optimization
- Performance Marketing
- Search Engine Marketing
- Email Marketing
- Content Marketing
- Social Media Marketing
- Display Advertising
- Marketing Analytics
- Web Analytics
- Affiliate Marketing
- MBA
- MBA in Finance
- MBA in HR
- MBA in Marketing
- MBA in Business Analytics
- MBA in Operations Management
- MBA in International Business
- MBA in Information Technology
- MBA in Healthcare Management
- MBA In General Management
- MBA in Agriculture
- MBA in Supply Chain Management
- MBA in Entrepreneurship
- MBA in Project Management
- Management Program
- Consumer Behaviour
- Supply Chain Management
- Financial Analytics
- Introduction to Fintech
- Introduction to HR Analytics
- Fundamentals of Communication
- Art of Effective Communication
- Introduction to Research Methodology
- Mastering Sales Technique
- Business Communication
- Fundamentals of Journalism
- Economics Masterclass
- Free Courses
String Replace in Python | Python String Replace
Updated on 03 July, 2023
6.23K+ views
• 8 min read
Table of Contents
Replacing characters and strings in Python is a crucial task when it comes to Data Cleaning or Text Processing. Your data might have formatting issues with garbage characters that need to be removed, the categories might be having spelling issues, etc. Also while text preprocessing for NLP based problems, string replacement is the most basic and important step while preparing the textual data.
In this tutorial, we will be going over multiple ways to replace different types of strings. If you are interested to get into data science, check out our data science certifications. By the end of this tutorial, you will have the knowledge of the following:
- Python replace() method
- Regex sub() method
- join() and filter()
- Replacing numeric data in strings
Replace() in Python
The string replace function in Python must be used to swap out one or more instances of a character or substring from the original string with the new character or substring. Strings are immutable, as we all know. As a result, the string replace in Python creates a copy of the updated string (the oldValues and newValues are switched).
Python replace()
The replace(old_str, new_str, count) method consists of 3 arguments:
- old_str: The string or a part of the string that needs to be replaced
- new_str: The string with which the old string needs to be replaced
- count: The count of times the particular string needs to be replaced
Return Value
Return Type: str
By replacing every instance of the old substring with a new one, this function creates a replica of the string. Only the first count occurrences are replaced if the optional argument count is provided.
If the oldValue that we provided as a parameter to replace() is not present in the original string, the original string is presented as the output.
Complexity
Time Complexity: O(n)
Space Complexity: O(n)
Replacing all errors with the correct word
Imagine that while writing an article for your project, you made a few typing mistakes throughout the piece. Using Python replace character in string, you can fix them all in a matter of seconds. For greater comprehension, let’s code this.
oldString = ‘CSE is an acronym for Computer Scince Engineering’.
newString = oldString.replace(‘Scince’, ‘Science’);
print(‘old string:’, oldString)
print(‘new string:’, newString)
Output:
old string: CSE is an acronym for Computer Scince Engineering.
new string: CSE is an acronym for Computer Science Engineering.
Replacing Full Forms to Abbreviations
Using the replace function, we can replace every full form that appears in the text with its corresponding abbreviation. For greater comprehension, let’s code this.
oldString = ‘Computer Science Engineering’
newString = oldString.replace(‘Computer Science Engineering’, ‘CSE’)
print(‘old string:’, oldString)
print(‘new string:’, newString)
Output:
old string: Computer Science Engineering.
new string: CSE
Let’s go over a few examples to understand the working.
Single replace
Mystr = “This is a sample string”
Newstr = Mystr.replace(‘is’, ‘was’)
Explore our Popular Data Science Degrees
#Output:
Thwas was a sample string
If you recall, Strings in Python are immutable. So when we call the replace method, it essentially makes another string object with the modified data. Moreover, we didn’t specify the count parameter in the above example. If not specified, the replace method will replace all the occurrences of the string.
Multiple replace
Mystr = “This is a sample string”
Newstr = Mystr.replace(“s”, “X”)
#Output:
ThiX iX a Xample Xtring
Multiple replace first n occurrences
If you only want first N occurrences,
Mystr = “This is a sample string”
Newstr = Mystr.replace(“s”, “X”, 3)
Top Essential Data Science Skills to Learn
#Output:
ThiX iX a Xample string
Multiple strings replace
In the above examples, we replaced one string a different number of times. Now what if you want to replace different strings in the same big string. We can write an effective function for it and get it done using the same method.
Consider the example as above, but now we want to replace “h”, “is” and “ng” with “X”.
def MultipleStrings(mainStr, strReplaceList, newStr):
# Iterating over the strings to be replaced
for elem in strReplaceList:
# Checking if string is in the main string
if elem in mainStr :
# Replace the string
mainStr = mainStr.replace(elem, newStr)
return mainStr
Mystr = “This is a sample string”
Newstr = MultipleStrings(Mystr, [‘h’, ‘is’, ‘ng’] , “X”)
#Output:
TXX X a sample striX
Read: Python Tutorial
Read our popular Data Science Articles
Replacing with regex
Python’s regex is a module specifically for dealing with text data – be it finding substrings, replacing strings or anything. Regex has the sub() function to find and replace/substitute substrings easily. Let’s go over its syntax and a few use cases.
The regex.sub(pattern, replacement, original_string) function takes 3 arguments:
- pattern: the substring that needs to be matched and replaced.
- replacement: can be a string which needs to be put in place, or a callable function which returns the value that needs to be put in place.
- original_string: the main string in which the substring has to be replaced.
Same as the replace method, regex also creates another string object with the modified string. Let’s go over a few working examples.
Removing whitespace
Whitespaces can be treated as special characters and replaced with other characters. In the below example, we intend to replace whitespaces with “X”.
import re
Mystr = “This is a sample string”
# Replace all whitespaces in Mystr with ‘X’
Newstr = re.sub(r”\s+”, ‘X’, Mystr)
#Output:
ThisXisXaXsampleXstring
As we see, all the whitespaces were replaced. The pattern is given by r”\s+” which means all the whitespace characters.
Removing all special characters
To remove all the special characters, we will pass a pattern which matches with all the special characters.
import re
import string
Mystr = “Tempo@@&[(000)]%%$@@66isit$$#$%-+Str”
pattern = r'[‘ + string.punctuation + ‘]’
# Replace all special characters in a string with X
Newstr = re.sub(pattern, ‘X’, Mystr)
#Output:
TempoXXXXX000XXXXXXX66isitXXXXXXXStr
Removing substring as case insensitive
In real life data, there might be cases where there might be many versions of the same word with different upper and lower case characters. To remove them all, putting all the words separately as the pattern wouldn’t be effective. The regex sub() function takes the flag re.IGNORECASE to ignore the cases. Let’s see how it works.
import re
Mystr = “This IS a sample Istring”
# Replace substring in a string with a case-insensitive approach
Newstr = re.sub(r’is’,‘**’, Mystr, flags=re.IGNORECASE)
#Output:
Th** ** a sample **tring
upGrad’s Exclusive Data Science Webinar for you –
Watch our Webinar on How to Build Digital & Data Mindset?
Removing multiple characters using regex
The regex function can easily remove multiple characters from a string. Below is an example.
import re
Mystr = “This is a sample string”
pattern = r'[hsa]’
# Remove characters ‘h’, ‘s’ and ‘a’ from a string
Newstr = re.sub(pattern, ”, Mystr)
#Output:
Ti i mple tring
Replacing using join()
Another way to remove or replace characters is to iterate through the string and check them against some condition.
charList = [‘h’, ‘s’, ‘a’]
Mystr = “This is a sample string”
# Remove all characters in list, from the string
Newstr = ”.join((elem for elem in Mystr if elem not in charList))
#Output:
Ti i mple tring
Replacing using join() and filter()
Above example can also be done by using the filter function.
Mystr = “This is a sample string”
charList = [‘h’, ‘s’, ‘a’]
# Remove all characters in list, from the string
Newstr = “”.join(filter(lambda k: k not in charList , Mystr))
#Output:
Ti i mple trying
Must Read: Fascinating Python Applications in Real World
Replacing numbers
Many times the numerical data is also present in the strings that might need to be removed and processed separately as a different feature. Let’s go over a few examples to see how these can be implemented.
Using regex
Consider the below string from which we need to remove the numeric data.
Mystr = “Sample string9211 of year 20xx”
pattern = r'[0-9]’
# Match all digits in the string and replace them by empty string
Newstr = re.sub(pattern, “”, Mystr)
#Output:
Sample string of year xx
In the above code, we use the matching pattern r'[0-9]’ to match for all the digits.
Using join() function
We can also iterate upon the string and filter out the digits using the isdigit() method which returns False for alphabets.
Mystr = “Sample string9211 of year 20xx”
# Iterates over the chars in the string and joins all characters except digits
Newstr = “”.join((item for item in Mystr if not item.isdigit()))
#Output:
Sample string of year xx
Using join() and filter()
Similarly, we can also put the filtering condition in the filter function to only return the characters which return True.
Mystr = “Sample string9211 of year 20xx”
# Filter all the digits from characters in string & join remaining chars
Newstr = “”.join(filter(lambda item: not item.isdigit(), Mystr))
#Output:
Sample string of year xx
Updating the Old Data with New Data
For instance, Facebook rebranded as Meta. The Python replace() method can be used to make changes to the documentation.
str =”Facebook is an online social media service platform. Facebook is an American international technology conglomerate based in California.”
str_replace =str.replace(“Facebook”,”Meta”)
print(“String after replace:”+str_replace)
Output:
Meta is an online social media service platform. Meta is an American international technology conglomerate based in California.
Before you go
We covered a lot of examples showing different ways to remove or replace characters/whitespaces/numbers from a string. We highly recommend you to try out more examples and different ways to do the above examples and also more examples of your own.
If you are curious to learn about python, data science, check out IIIT-B & upGrad’s Executive PG Programme in Data Science which is created for working professionals and offers 10+ case studies & projects, practical hands-on workshops, mentorship with industry experts, 1-on-1 with industry mentors, 400+ hours of learning and job assistance with top firms.
Frequently Asked Questions (FAQs)
1. What is the need for the string replace method in Python?
This function becomes very useful when you are applying data cleansing techniques to it. Unnecessary or garbage characters can be easily removed using this function. Replacing strings or characters is not only used in data cleansing but also in processing problems of NLP.
Having these types of methods to deal with strings is important as the whole data science field deals with huge chunks of data.
2. What are the advantages of using string data types?
Strings are useful as you can store large amounts of data with ease using this data type. Python supports a good number of useful methods to perform operations on strings. Also, strings are mutable in Python which reduces the error generation and they are less expensive as well.
The string is one of the most used built-in data types in Python. Not only in python, but many other languages also support this as a pre-defined data type and support various methods to operate on them.