Having collection of items, what is the fastest way to find (structured) value in it?
Is Dictionary<TKey,TValue> the best option here, or should we use good ol' array when
collection is short?
BenchmarkDotNet=v0.13.1, OS=Windows 10.0.19044.1889 (21H2)
Intel Core i7-7820HQ CPU 2.90GHz (Kaby Lake), 1 CPU, 8 logical and 4 physical cores
.NET SDK=6.0.303
[Host] : .NET 6.0.8 (6.0.822.36306), X64 RyuJIT
ShortRun : .NET 6.0.8 (6.0.822.36306), X64 RyuJIT
Job=ShortRun IterationCount=3 LaunchCount=1
WarmupCount=3| Method | Categories | Size | Mean | Error | StdDev | Ratio | RatioSD |
|---|---|---|---|---|---|---|---|
| ArrayLookupFirst | First | 4 | 0.5657 ns | 0.6618 ns | 0.0363 ns | 1.00 | 0.00 |
| ListLookupFirst | First | 4 | 0.7152 ns | 2.2651 ns | 0.1242 ns | 1.27 | 0.26 |
| DictLookupFirst | First | 4 | 8.3127 ns | 17.2711 ns | 0.9467 ns | 14.66 | 0.71 |
| ArrayLookupLast | Last | 4 | 2.7694 ns | 2.1951 ns | 0.1203 ns | 1.00 | 0.00 |
| ListLookupLast | Last | 4 | 3.7819 ns | 0.8409 ns | 0.0461 ns | 1.37 | 0.07 |
| DictLookupLast | Last | 4 | 7.5195 ns | 0.4922 ns | 0.0270 ns | 2.72 | 0.13 |
| ArrayLookupMissing | Missing | 4 | 2.3032 ns | 0.4549 ns | 0.0249 ns | 1.00 | 0.00 |
| ListLookupMissing | Missing | 4 | 3.8810 ns | 0.1269 ns | 0.0070 ns | 1.69 | 0.02 |
| DictLookupMissing | Missing | 4 | 7.2522 ns | 0.1733 ns | 0.0095 ns | 3.15 | 0.03 |
| ArrayLookupFirst | First | 16 | 0.5052 ns | 0.2029 ns | 0.0111 ns | 1.00 | 0.00 |
| ListLookupFirst | First | 16 | 0.6597 ns | 0.3617 ns | 0.0198 ns | 1.31 | 0.04 |
| DictLookupFirst | First | 16 | 10.1857 ns | 0.8382 ns | 0.0459 ns | 20.17 | 0.52 |
| DictLookupLast | Last | 16 | 7.9673 ns | 3.2842 ns | 0.1800 ns | 0.81 | 0.02 |
| ArrayLookupLast | Last | 16 | 9.7905 ns | 0.1535 ns | 0.0084 ns | 1.00 | 0.00 |
| ListLookupLast | Last | 16 | 19.7667 ns | 0.5566 ns | 0.0305 ns | 2.02 | 0.00 |
| ArrayLookupMissing | Missing | 16 | 9.2578 ns | 0.7516 ns | 0.0412 ns | 1.00 | 0.00 |
| DictLookupMissing | Missing | 16 | 9.7767 ns | 2.0647 ns | 0.1132 ns | 1.06 | 0.01 |
| ListLookupMissing | Missing | 16 | 20.8642 ns | 20.2916 ns | 1.1123 ns | 2.25 | 0.12 |
| ArrayLookupFirst | First | 64 | 0.6314 ns | 2.2446 ns | 0.1230 ns | 1.00 | 0.00 |
| ListLookupFirst | First | 64 | 0.6692 ns | 0.1592 ns | 0.0087 ns | 1.09 | 0.25 |
| DictLookupFirst | First | 64 | 9.1905 ns | 1.4587 ns | 0.0800 ns | 15.00 | 3.39 |
| DictLookupLast | Last | 64 | 8.2250 ns | 0.4255 ns | 0.0233 ns | 0.21 | 0.01 |
| ArrayLookupLast | Last | 64 | 39.8194 ns | 24.4838 ns | 1.3420 ns | 1.00 | 0.00 |
| ListLookupLast | Last | 64 | 83.4625 ns | 3.3309 ns | 0.1826 ns | 2.10 | 0.07 |
| DictLookupMissing | Missing | 64 | 9.3276 ns | 3.7162 ns | 0.2037 ns | 0.25 | 0.01 |
| ArrayLookupMissing | Missing | 64 | 37.3394 ns | 18.2431 ns | 1.0000 ns | 1.00 | 0.00 |
| ListLookupMissing | Missing | 64 | 88.5167 ns | 17.1972 ns | 0.9426 ns | 2.37 | 0.09 |
| ArrayLookupFirst | First | 128 | 0.5633 ns | 0.1721 ns | 0.0094 ns | 1.00 | 0.00 |
| ListLookupFirst | First | 128 | 0.8455 ns | 0.3225 ns | 0.0177 ns | 1.50 | 0.03 |
| DictLookupFirst | First | 128 | 7.8288 ns | 7.4080 ns | 0.4061 ns | 13.91 | 0.92 |
| DictLookupLast | Last | 128 | 7.1141 ns | 0.4536 ns | 0.0249 ns | 0.09 | 0.00 |
| ArrayLookupLast | Last | 128 | 78.2129 ns | 5.4081 ns | 0.2964 ns | 1.00 | 0.00 |
| ListLookupLast | Last | 128 | 183.4996 ns | 109.4804 ns | 6.0010 ns | 2.35 | 0.07 |
| DictLookupMissing | Missing | 128 | 7.2917 ns | 2.1516 ns | 0.1179 ns | 0.10 | 0.00 |
| ArrayLookupMissing | Missing | 128 | 75.5424 ns | 0.8904 ns | 0.0488 ns | 1.00 | 0.00 |
| ListLookupMissing | Missing | 128 | 178.0170 ns | 87.1320 ns | 4.7760 ns | 2.36 | 0.06 |
| ListLookupFirst | First | 512 | 0.5178 ns | 0.4412 ns | 0.0242 ns | 0.96 | 0.15 |
| ArrayLookupFirst | First | 512 | 0.5450 ns | 1.1779 ns | 0.0646 ns | 1.00 | 0.00 |
| DictLookupFirst | First | 512 | 10.2390 ns | 2.2026 ns | 0.1207 ns | 18.94 | 1.91 |
| DictLookupLast | Last | 512 | 7.5507 ns | 1.4540 ns | 0.0797 ns | 0.02 | 0.00 |
| ArrayLookupLast | Last | 512 | 332.8749 ns | 87.7630 ns | 4.8106 ns | 1.00 | 0.00 |
| ListLookupLast | Last | 512 | 703.5220 ns | 286.6291 ns | 15.7111 ns | 2.11 | 0.03 |
| DictLookupMissing | Missing | 512 | 5.7155 ns | 2.8976 ns | 0.1588 ns | 0.02 | 0.00 |
| ArrayLookupMissing | Missing | 512 | 328.8062 ns | 24.9660 ns | 1.3685 ns | 1.00 | 0.00 |
| ListLookupMissing | Missing | 512 | 699.8624 ns | 333.4925 ns | 18.2798 ns | 2.13 | 0.06 |