Python re module
1. What is the re Module?
The re module is used for Regular Expressions in Python.
In simple words:
👉 It helps you search text
👉 It helps you match patterns
👉 It helps you replace text
2. Why Use the re Module?
We use re to:
✔ Find words
✔ Validate emails & phone numbers
✔ Extract numbers
✔ Replace text easily
3. Import the re Module
Example
4. re.search() – Find First Match
Searches for a pattern anywhere in text.
Example
5. re.findall() – Find All Matches
Returns all matching results as a list.
Example
Output:
6. re.match() – Match from Start Only
Checks pattern only at the beginning.
Example
7. re.fullmatch() – Match Entire String
Example
8. re.sub() – Replace Text
Example
Output:
9. re.split() – Split Text
Example
10. Common RegEx Patterns
| Pattern | Meaning |
|---|---|
\d |
Digit |
\w |
Word character |
\s |
Space |
. |
Any character |
^ |
Start |
$ |
End |
+ |
One or more |
* |
Zero or more |
11. Find Numbers in Text
Example
12. Validate Email (Simple)
Example
13. Validate Phone Number
Example
14. Case-Insensitive Search
Example
15. Common Beginner Mistakes
❌ Forgetting to import re
❌ Using wrong patterns
❌ Forgetting raw strings r""
❌ Confusing search() and match()
16. Simple Practice Examples
Example 1: Find All Digits
Example 2: Replace Spaces
Example 3: Check Username
17. Summary (Python re Module)
✔ Used for pattern matching
✔ Powerful text search tool
✔ Supports validation & replacement
✔ Used in real-world programs
✔ Needs practice to master
📘 Perfect for Beginner & Intermediate eBook
This chapter is ideal for:
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Python learners
-
Text processing
-
Input validation
-
Interview preparation
If you want next, I can write:
-
Advanced RegEx
-
Password Validation Using RegEx
-
RegEx Mini Projects
-
Python Interview Questions
Just tell me 😊
