How to Truncate a String with Ellipsis in Python

A function that shortens text to a maximum length and appends an ellipsis when truncation occurs, handling edge cases.

Easy Python 3.9+ Aug 9, 2026 Strings & text 11 views 0 copies

strings truncation text-processing ellipsis

Python code

18 lines

Python 3.9+

def truncate_with_ellipsis(text: str, max_length: int) -> str:
    """Truncate text to max_length, appending ellipsis if truncated."""
    if len(text) <= max_length:
        return text
    if max_length <= 3:
        return text[:max_length]
    return text[: max_length - 3] + "..."

if __name__ == "__main__":
    test_cases = [
        ("Hello, world!", 10),
        ("Python", 10),
        ("Truncation test case", 8),
        ("Short", 3),
        ("abcdef", 3),
    ]
    for text, max_len in test_cases:
        print(f"{text!r} at {max_len} -> {truncate_with_ellipsis(text, max_len)!r}")

Output

stdout

'Hello, world!' at 10 -> 'Hello worl...'
'Python' at 10 -> 'Python'
'Truncation test case' at 8 -> 'Truncat...'
'Short' at 3 -> 'Sho'
'abcdef' at 3 -> 'abc'

How it works

The function first checks if the text fits within the limit and returns it unchanged when it does. For longer text, it reserves 3 characters for the ellipsis and slices the original string accordingly. The edge case of max_length <= 3 prevents slicing with negative indices, which would produce incorrect results. Using string slicing text[:max_length - 3] is efficient and readable. The function preserves the original string type and handles all standard text inputs gracefully.

Common mistakes

Forgetting to handle `max_length <= 3` which causes negative slice indices
Using `max_length - 3` without checking if the result is positive
Appending the ellipsis even when the text fits within the limit
Not accounting for ellipsis length in the total character count

Variations

Use `textwrap.shorten(text, width=max_length, placeholder='...')` for the same effect with configurable placeholder

Real-world use cases

Displaying truncated file names or titles in a UI list view when the full name exceeds the column width.
Logging truncated error messages to keep log lines within a fixed character budget for better readability.
Creating preview text snippets for search results or article cards without exceeding layout constraints.

How to Truncate a String with Ellipsis in Python

Python code

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How it works

Common mistakes

Variations

Real-world use cases

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