array_key_exists

名前:array_key_exists

カテゴリ:配列

対応言語:php

一言説明:指定されたキー名が配列に存在するかどうかを確認します。

例

例1

キー名「Volvo」が配列に存在するかどうかを確認します。

 <span class="token php language-php"><span class="token delimiter important"><？php</span>
<span class="token variable">$ a</span> <span class="token operator">=</span> <span class="token keyword">array</span> <span class="token punctuation">（</span> <span class="token string double-quoted-string">"volvo"</span> <span class="token operator">=></span> <span class="token string double-quoted-string">"xc90"</span> <span class="token punctuation">、</span> <span class="token string double-quoted-string">"bmw"</span> <span class="token operator">=></span> <span class="token string double-quoted-string">"x5"</span> <span class="token punctuation">）</span> <span class="token punctuation">;</span>
<span class="token keyword">もし</span><span class="token punctuation">（</span><span class="token function"></span></span><mark> <span class="token function">array_key_exists</span> <span class="token punctuation">（</span> <span class="token string double-quoted-string">"volvo"</span> <span class="token punctuation">、</span> <span class="token variable">$ a</span> <span class="token punctuation">）</span></mark><span class="token punctuation"></span> <span class="token punctuation">））</span>
  <span class="token punctuation">{</span>
  <span class="token keyword">エコー</span><span class="token string double-quoted-string">「キーが存在します！」</span> <span class="token punctuation">;</span>
  <span class="token punctuation">}</span>
<span class="token keyword">それ以外</span>
  <span class="token punctuation">{</span>
  <span class="token keyword">エコー</span><span class="token string double-quoted-string">「鍵は存在しません！」</span> <span class="token punctuation">;</span>
  <span class="token punctuation">}</span>
<span class="token delimiter important">？></span>

自分で試してみてください

例2

キー名「トヨタ」が配列に存在するかどうかを確認してください。

 <span class="token php language-php"><span class="token delimiter important"><？php</span>
<span class="token variable">$ a</span> <span class="token operator">=</span> <span class="token keyword">array</span> <span class="token punctuation">（</span> <span class="token string double-quoted-string">"volvo"</span> <span class="token operator">=></span> <span class="token string double-quoted-string">"xc90"</span> <span class="token punctuation">、</span> <span class="token string double-quoted-string">"bmw"</span> <span class="token operator">=></span> <span class="token string double-quoted-string">"x5"</span> <span class="token punctuation">）</span> <span class="token punctuation">;</span>
<span class="token keyword">もし</span><span class="token punctuation">（</span><span class="token function"></span></span><mark> <span class="token function">key_exists</span> <span class="token punctuation">（</span> <span class="token string double-quoted-string">"Toyota"</span> <span class="token punctuation">、</span> <span class="token variable">$ a</span> <span class="token punctuation">）</span></mark><span class="token punctuation"></span> <span class="token punctuation">））</span>
  <span class="token punctuation">{</span>
  <span class="token keyword">エコー</span><span class="token string double-quoted-string">「キーが存在します！」</span> <span class="token punctuation">;</span>
  <span class="token punctuation">}</span>
<span class="token keyword">それ以外</span>
  <span class="token punctuation">{</span>
  <span class="token keyword">エコー</span><span class="token string double-quoted-string">「鍵は存在しません！」</span> <span class="token punctuation">;</span>
  <span class="token punctuation">}</span>
<span class="token delimiter important">？></span>

自分で試してみてください

例3

整数キー名「0」が配列に存在するかどうかを確認します。

 <span class="token php language-php"><span class="token delimiter important"><？php</span>
<span class="token variable">$ a</span> <span class="token operator">=</span> <span class="token keyword">array</span> <span class="token punctuation">（</span> <span class="token string double-quoted-string">"volvo"</span> <span class="token punctuation">、</span> <span class="token string double-quoted-string">"bmw"</span> <span class="token punctuation">）</span> <span class="token punctuation">;</span>
<span class="token keyword">もし</span><span class="token punctuation">（</span><span class="token function"></span></span><mark> <span class="token function">array_key_exists</span> <span class="token punctuation">（</span> <span class="token number">0</span> <span class="token punctuation">、</span> <span class="token variable">$ a</span> <span class="token punctuation">）</span></mark><span class="token punctuation"></span> <span class="token punctuation">））</span>
  <span class="token punctuation">{</span>
  <span class="token keyword">エコー</span><span class="token string double-quoted-string">「キーが存在します！」</span> <span class="token punctuation">;</span>
  <span class="token punctuation">}</span>
<span class="token keyword">それ以外</span>
  <span class="token punctuation">{</span>
  <span class="token keyword">エコー</span><span class="token string double-quoted-string">「鍵は存在しません！」</span> <span class="token punctuation">;</span>
  <span class="token punctuation">}</span>
<span class="token delimiter important">？></span>

自分で試してみてください