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68f827d9bf
* perf: optimize Substring to work directly with strings instead of converting to runes
- Rewrite Substring to iterate over string bytes directly, avoiding full []rune conversion
- Improve performance for long strings by only processing necessary portions
- Add comprehensive test cases for Unicode handling, invalid UTF-8, and edge cases
- Add BenchmarkSubstring to measure performance improvements
- Improve documentation with detailed parameter descriptions
- Handle invalid UTF-8 sequences by converting to []rune when needed
Bencstat:
│ old.txt │ new.txt │
│ sec/op │ sec/op vs base │
Substring/{10_10}-4 558.85n ± 9% 39.75n ± 10% -92.89% (p=0.000 n=8)
Substring/{50_50}-4 783.10n ± 6% 85.15n ± 5% -89.13% (p=0.000 n=8)
Substring/{50_45}-4 773.30n ± 3% 126.5n ± 7% -83.65% (p=0.000 n=8)
Substring/{-50_50}-4 794.00n ± 2% 177.6n ± 7% -77.63% (p=0.000 n=8)
Substring/{-10_10}-4 542.85n ± 20% 41.82n ± 6% -92.30% (p=0.000 n=8)
geomean 680.4n 79.52n -88.31%
│ old.txt │ new.txt │
│ B/op │ B/op vs base │
Substring/{10_10}-4 432.0 ± 0% 0.0 ± 0% -100.00% (p=0.000 n=8)
Substring/{50_50}-4 480.0 ± 0% 0.0 ± 0% -100.00% (p=0.000 n=8)
Substring/{50_45}-4 464.0 ± 0% 0.0 ± 0% -100.00% (p=0.000 n=8)
Substring/{-50_50}-4 480.0 ± 0% 0.0 ± 0% -100.00% (p=0.000 n=8)
Substring/{-10_10}-4 432.0 ± 0% 0.0 ± 0% -100.00% (p=0.000 n=8)
│ old.txt │ new.txt │
│ allocs/op │ allocs/op vs base │
Substring/{10_10}-4 2.000 ± 0% 0.000 ± 0% -100.00% (p=0.000 n=8)
Substring/{50_50}-4 2.000 ± 0% 0.000 ± 0% -100.00% (p=0.000 n=8)
Substring/{50_45}-4 2.000 ± 0% 0.000 ± 0% -100.00% (p=0.000 n=8)
Substring/{-50_50}-4 2.000 ± 0% 0.000 ± 0% -100.00% (p=0.000 n=8)
Substring/{-10_10}-4 2.000 ± 0% 0.000 ± 0% -100.00% (p=0.000 n=8)
* Enhance substring documentation with Unicode details
Returns a substring starting at the given offset with the specified length. Supports negative offsets; out-of-bounds are clamped. Operates on Unicode runes (characters) and is optimized for zero allocations.
---------
Co-authored-by: Samuel Berthe <dev@samuel-berthe.fr>
1.4 KiB
1.4 KiB
name, slug, sourceRef, category, subCategory, playUrl, variantHelpers, similarHelpers, position, signatures
| name | slug | sourceRef | category | subCategory | playUrl | variantHelpers | similarHelpers | position | signatures | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Substring | substring | string.go#L105 | core | string | https://go.dev/play/p/TQlxQi82Lu1 |
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10 |
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Returns a substring starting at the given offset with the specified length. Supports negative offsets; out-of-bounds are clamped. Operates on Unicode runes (characters) and is optimized for zero allocations.
// Basic usage
result := lo.Substring("hello", 2, 3)
// result: "llo"
// Negative offset - counts from end
result = lo.Substring("hello", -4, 3)
// result: "ell"
// Length longer than string - clamped to available characters
result = lo.Substring("hello", 1, 10)
// result: "ello" (only 4 characters available from position 1)
// Zero length - returns empty string
result = lo.Substring("hello", 1, 0)
// result: ""
// Offset beyond string length - returns empty string
result = lo.Substring("hello", 10, 3)
// result: ""
// With Unicode strings (rune-aware)
result = lo.Substring("héllo", 1, 3)
// result: "él"
// Negative offset with negative values clamped
result = lo.Substring("hello", -10, 3)
// result: "hel" (offset clamped to 0)