29 lines
1.7 KiB
HTML
29 lines
1.7 KiB
HTML
<html><head><object type="application/x-oleobject" classid="clsid:1e2a7bd0-dab9-11d0-b93a-00c04fc99f9e">
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<param name="Keyword" value="First">
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<param name="Keyword" value="FirstOrDefault">
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</object><meta http-equiv="Content-Type" content="text/html; charset=windows-1251"><title></title><link rel="StyleSheet" href="../../../default.css"></head>
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<body>
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<H1>Ìåòîäû First, FirstOrDefault</H1><h2>Îïèñàíèå ìåòîäîâ</h2><p>Ìåòîäû ïðèâåäåíû äëÿ ïîñëåäîâàòåëüíîñòè <code><b>sequence of</b> T</code>.</p><table>
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<tr><td>
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<code><b>function </b>First(): T;</code>
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<br> Âîçâðàùàåò ïåðâûé ýëåìåíò ïîñëåäîâàòåëüíîñòè.
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</td></tr>
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<tr><td>
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<code><b>function </b>First(predicate: T->boolean): T;</code>
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<br> Âîçâðàùàåò ïåðâûé ýëåìåíò ïîñëåäîâàòåëüíîñòè, óäîâëåòâîðÿþùèé óêàçàííîìó óñëîâèþ.
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</td></tr>
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<tr><td>
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<code><b>function </b>FirstOrDefault(): T;</code>
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<br> Âîçâðàùàåò ïåðâûé ýëåìåíò ïîñëåäîâàòåëüíîñòè èëè çíà÷åíèå ïî óìîë÷àíèþ, åñëè ïîñëåäîâàòåëüíîñòü íå ñîäåðæèò ýëåìåíòîâ.
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</td></tr>
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<tr><td>
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<code><b>function </b>FirstOrDefault(predicate: T->boolean): T;</code>
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<br> Âîçâðàùàåò ïåðâûé óäîâëåòâîðÿþùèé óñëîâèþ ýëåìåíò ïîñëåäîâàòåëüíîñòè èëè çíà÷åíèå ïî óìîë÷àíèþ, åñëè íè îäíîãî òàêîãî ýëåìåíòà íå íàéäåíî.
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</td></tr>
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</table>
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<h2>Ïðèìåð </h2><blockquote><code><strong>begin</strong><br> <strong>var</strong>
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a := Arr(1,2,3,4);<br> Println(a.Skip(2).First); // 3<br>
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Println(a.First(x -> x <strong>mod</strong> 2 = 0); // 2<br>
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Println(a.FirstOrDefault(x -> x>5); // 0 <br><strong>end</strong>.</code></blockquote>
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</body>
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