perf: optimize it.ContainsBy/EveryBy/SomeBy/NoneBy to avoid unnecessary allocations#812
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samber merged 2 commits intosamber:masterfrom Feb 24, 2026
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…ssary allocations
Replace intermediate iterator chains with direct loops and early returns.
The direct loops with early return eliminate intermediate iterator
creation from Filter(), Reject(), IsNotEmpty() and IsEmpty() functions.
Benchmark results (benchstat):
│ old.txt │ new.txt │
│ sec/op │ sec/op vs base │
ItContainsBy/ints_10-4 807.2n ± 54% 151.0n ± 6% -81.29% (p=0.000 n=8)
ItContainsBy/ints_100-4 2.447µ ± 14% 1.531µ ± 11% -37.42% (p=0.000 n=8)
ItContainsBy/ints_1000-4 17.67µ ± 4% 13.85µ ± 4% -21.64% (p=0.000 n=8)
ItEveryBy/ints_10-4 1022.5n ± 63% 208.0n ± 34% -79.66% (p=0.000 n=8)
ItEveryBy/ints_100-4 5.640µ ± 36% 1.542µ ± 9% -72.67% (p=0.000 n=8)
ItEveryBy/ints_1000-4 52.22µ ± 54% 19.29µ ± 16% -63.06% (p=0.000 n=8)
ItSomeBy/ints_10-4 2227.5n ± 43% 187.1n ± 14% -91.60% (p=0.000 n=8)
ItSomeBy/ints_100-4 4.611µ ± 22% 1.691µ ± 10% -63.32% (p=0.000 n=8)
ItSomeBy/ints_1000-4 39.41µ ± 27% 22.61µ ± 24% -42.63% (p=0.000 n=8)
ItNoneBy/ints_10-4 1657.5n ± 34% 196.3n ± 21% -88.15% (p=0.000 n=8)
ItNoneBy/ints_100-4 4.503µ ± 20% 1.743µ ± 12% -61.30% (p=0.000 n=8)
ItNoneBy/ints_1000-4 29.39µ ± 29% 16.66µ ± 15% -43.32% (p=0.000 n=8)
geomean 5.591µ 1.747µ -68.76%
│ old.txt │ new.txt │
│ B/op │ B/op vs base │
ItContainsBy/ints_10-4 200.0 ± 0% 0.0 ± 0% -100.00% (p=0.000 n=8)
ItContainsBy/ints_100-4 200.0 ± 0% 0.0 ± 0% -100.00% (p=0.000 n=8)
ItContainsBy/ints_1000-4 200.0 ± 0% 0.0 ± 0% -100.00% (p=0.000 n=8)
ItEveryBy/ints_10-4 184.0 ± 0% 0.0 ± 0% -100.00% (p=0.000 n=8)
ItEveryBy/ints_100-4 184.0 ± 0% 0.0 ± 0% -100.00% (p=0.000 n=8)
ItEveryBy/ints_1000-4 184.0 ± 0% 0.0 ± 0% -100.00% (p=0.000 n=8)
ItSomeBy/ints_10-4 200.0 ± 0% 0.0 ± 0% -100.00% (p=0.000 n=8)
ItSomeBy/ints_100-4 200.0 ± 0% 0.0 ± 0% -100.00% (p=0.000 n=8)
ItSomeBy/ints_1000-4 200.0 ± 0% 0.0 ± 0% -100.00% (p=0.000 n=8)
ItNoneBy/ints_10-4 200.0 ± 0% 0.0 ± 0% -100.00% (p=0.000 n=8)
ItNoneBy/ints_100-4 200.0 ± 0% 0.0 ± 0% -100.00% (p=0.000 n=8)
ItNoneBy/ints_1000-4 200.0 ± 0% 0.0 ± 0% -100.00% (p=0.000 n=8)
│ old.txt │ new.txt │
│ allocs/op │ allocs/op vs base │
ItContainsBy/ints_10-4 7.000 ± 0% 0.000 ± 0% -100.00% (p=0.000 n=8)
ItContainsBy/ints_100-4 7.000 ± 0% 0.000 ± 0% -100.00% (p=0.000 n=8)
ItContainsBy/ints_1000-4 7.000 ± 0% 0.000 ± 0% -100.00% (p=0.000 n=8)
ItEveryBy/ints_10-4 6.000 ± 0% 0.000 ± 0% -100.00% (p=0.000 n=8)
ItEveryBy/ints_100-4 6.000 ± 0% 0.000 ± 0% -100.00% (p=0.000 n=8)
ItEveryBy/ints_1000-4 6.000 ± 0% 0.000 ± 0% -100.00% (p=0.000 n=8)
ItSomeBy/ints_10-4 7.000 ± 0% 0.000 ± 0% -100.00% (p=0.000 n=8)
ItSomeBy/ints_100-4 7.000 ± 0% 0.000 ± 0% -100.00% (p=0.000 n=8)
ItSomeBy/ints_1000-4 7.000 ± 0% 0.000 ± 0% -100.00% (p=0.000 n=8)
ItNoneBy/ints_10-4 7.000 ± 0% 0.000 ± 0% -100.00% (p=0.000 n=8)
ItNoneBy/ints_100-4 7.000 ± 0% 0.000 ± 0% -100.00% (p=0.000 n=8)
ItNoneBy/ints_1000-4 7.000 ± 0% 0.000 ± 0% -100.00% (p=0.000 n=8)
samber
approved these changes
Feb 24, 2026
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Replace intermediate iterator chains with direct loops and early returns.
The direct loops with early return eliminate intermediate iterator creation from Filter(), Reject(), IsNotEmpty() and IsEmpty() functions.
Benchmark results (benchstat):