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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
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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.

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