Next
1. Read File2. Write File3. Append to File4. Read CSV File5. Write CSV File6. JSON Read7. JSON Write8. File Copy9. File Rename10. Read Binary File11. Write Binary File12. Count Words in File13. Count Lines in File14. Count Characters in File15. Search Substring in File16. Iterate File Lines17. File Metadata18. File Compression19. File Decompression20. Delete File

Search Substring in File in Python

Search for a substring in a text file and report matching line numbers.

BeginnerFile Handling ProgramsExample 15 of 20
search-substring-in-file.py
Run in browser
1# Program to search for a substring in a file
2

3filename = input("Enter filename: ")
4term = input("Enter search term: ")
5

6try:
7    with open(filename, "r", encoding="utf-8") as f:
8        for line_no, line in enumerate(f, start=1):
9            if term in line:
10                print(f"Found on line {line_no}: {line.strip()}")
11except FileNotFoundError:
12    print("File not found.")

Output

Enter filename: notes.txt
Enter search term: Python
Found on line 3: Learning Python basics

What's going on

Reads file line by line, checking membership of the substring and printing matching lines.

PreviousCount Characters in FileNextIterate File Lines