array_key_exists
配列に指定されたキー名またはインデックスがあるかどうかを確認します
日本語
日本語
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>
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>
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>
array_intersect_assoc
array_fill
array_flip
array_replace
array_search
array_diff_key
array_change_key_case
array_rand
