philiprehberger-diff-strings

Show character-level differences between two strings with colored terminal output.

Installation

pip install philiprehberger-diff-strings

Usage

from philiprehberger_diff_strings import diff

print(diff("hello world", "hello there"))

Character-level diff

from philiprehberger_diff_strings import diff

# Colored output (default)
print(diff("the cat sat", "the bat sat"))

# Plain text output
print(diff("the cat sat", "the bat sat", color=False))

Programmatic diff

from philiprehberger_diff_strings import char_diff

changes = char_diff("abc", "adc")
# [Match(text='a'), Replace(old='b', new='d'), Match(text='c')]

Word-level diff

from philiprehberger_diff_strings import word_diff

print(word_diff("the quick brown fox", "the slow brown dog", color=False))

Line-level diff

from philiprehberger_diff_strings import line_diff

a = "line one\nline two\nline three"
b = "line one\nline 2\nline three"
print(line_diff(a, b, color=False))
# Shows unified-diff style output with +/- markers

# Control context lines shown around changes
print(line_diff(a, b, context=1))

Diff summary

from philiprehberger_diff_strings import diff_summary

summary = diff_summary("hello world", "hello there")
print(summary.additions)   # number of insertions
print(summary.deletions)   # number of deletions
print(summary.changes)     # number of replacements
print(summary.similarity)  # similarity ratio (0.0 to 1.0)

HTML diff

from philiprehberger_diff_strings import html_diff

result = html_diff("the cat", "the bat")
# 'the <del>c</del><ins>b</ins>at'

Markdown diff

For PR comments, issue bodies, or chat messages — render the diff using Markdown formatting (**bold** insertions, ~~strikethrough~~ deletions):

from philiprehberger_diff_strings import markdown_diff

print(markdown_diff("the cat sat", "the bat sat"))
# 'the ~~c~~**b**at sat'

Custom colors

from philiprehberger_diff_strings import diff, word_diff

# Use custom ANSI colors (red, green, yellow, blue, magenta, cyan)
print(diff("abc", "adc", insert_color="cyan", delete_color="magenta", replace_color="blue"))
print(word_diff("old text", "new text", insert_color="blue", replace_color="cyan"))

Patch (reconstruct from changes)

from philiprehberger_diff_strings import char_diff, patch

changes = char_diff("hello world", "hello there")
result = patch("hello world", changes)
assert result == "hello there"

Similarity ratio

from philiprehberger_diff_strings import similarity

score = similarity("hello", "hallo")  # 0.8

Test assertions

from philiprehberger_diff_strings import assert_strings_equal

assert_strings_equal("expected output", "expected output")  # passes
assert_strings_equal("expected", "actual")  # raises AssertionError with diff

API

Function	Description
diff(a, b, *, color=True, insert_color="green", delete_color="red", replace_color="yellow")	Character-level diff as a string
char_diff(a, b)	Programmatic diff returning a list of Change objects
word_diff(a, b, *, color=True, insert_color="green", delete_color="red", replace_color="yellow")	Word-level diff as a string
line_diff(a, b, *, color=True, context=3)	Unified-style line-level diff
diff_summary(a, b)	Summary with addition/deletion/change counts and similarity
html_diff(a, b)	Character-level diff as HTML with <ins>/<del> tags
markdown_diff(a, b)	Character-level diff as Markdown (**bold** for inserts, ~~strikethrough~~ for deletes)
patch(original, changes)	Reconstruct the modified string from a change list
similarity(a, b)	Similarity ratio between 0.0 and 1.0
assert_strings_equal(expected, actual, *, msg="")	Assert equal or raise with diff

Change types

Type	Fields	Description
Match(text)	text: str	Unchanged text
Insert(text)	text: str	Text added in the second string
Delete(text)	text: str	Text removed from the first string
Replace(old, new)	old: str, new: str	Text that changed between strings

DiffSummary

Field	Type	Description
additions	int	Number of insertion operations
deletions	int	Number of deletion operations
changes	int	Number of replacement operations
similarity	float	Similarity ratio between 0.0 and 1.0

Development

pip install -e .
python -m pytest tests/ -v

Support

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License

MIT