Dokážete spočítat, kolikrát jste napsali něco jako:
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| var prime = new bool[1000]; | |
| for ( int i = 0; i < isPrime.Length; i++ ) | |
| { | |
| prime[i] = true; | |
| } |
Nebo, pokud milujete LINQ, (a nevadí vám mírně horší výkonnost)?
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| var prime = Enumerable.Repeat(true, 1000).ToArray(); |
Pokud jste odpověděli “nekonečněkrát” či více, vyzkoušejte nový způsob k dispozici v .NET Core 2.0 a novějších:
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| var data = new bool[1000]; | |
| Array.Fill(data, true); |
Array.Fill přináší to nejlepší z obou světů – je stručnější než ručně psaný for cyklus zatímco je rychlejší než Enumerable.Repeat.
A protože je .NET Core open source můžeme se podívat přímo pod kapotu na implementaci metody Array.Fill a všimnout si, že jde vlastně pouze o zkratku pro celý for cyklus:
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| public static void Fill<T>(T[] array, T value) | |
| { | |
| if (array == null) | |
| { | |
| ThrowHelper.ThrowArgumentNullException(ExceptionArgument.array); | |
| } | |
| for (int i = 0; i < array.Length; i++) | |
| { | |
| array[i] = value; | |
| } | |
| } |
Stojí také za zmínku, že Array.Fill má další overload který dovoluje specifikovat rozsah indexů, které mají být vyplněny:
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| public static void Fill<T> (T[] array, T value, int startIndex, int count); |
