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

Iterate File Lines in Python

for line in f: under with open(...). File closes even if you break or explode.

BeginnerFile Handling ProgramsExample 16 of 20
iterate-file-lines.py
1# Program to iterate over file lines
2

3filename = input("Enter filename: ")
4

5try:
6    with open(filename, "r", encoding="utf-8") as f:
7        for line_no, line in enumerate(f, start=1):
8            print(f"{line_no}: {line.strip()}")
9except FileNotFoundError:
10    print("File not found.")

Output

Enter filename: notes.txt
1: First line
2: Second line
...

What's going on

Shows the canonical pattern 'with open(...) as f' and enumeration of lines.

After this program

If the idea is still fuzzy, read Day 14: File Handling in the Python course. For a short check, try the Python quiz (300 questions). Stay with all 20 file handling programs, or see every topic on Python exercises.

PreviousSearch Substring in FileNextFile Metadata