array_keys

例

例1

配列内のすべてのキー名を含む新しい配列を返します。

 <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 string double-quoted-string">"Toyota"</span> <span class="token operator">=></span> <span class="token string double-quoted-string">"Highlander"</span> <span class="token punctuation">）</span> <span class="token punctuation">;</span>
<span class="token function">print_r</span> <span class="token punctuation">（</span><span class="token function"></span></span><mark> <span class="token function">array_keys</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 delimiter important">？></span>

自分で試してみてください

例2

値パラメーターを使用します。

 <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 string double-quoted-string">"Toyota"</span> <span class="token operator">=></span> <span class="token string double-quoted-string">"Highlander"</span> <span class="token punctuation">）</span> <span class="token punctuation">;</span>
<span class="token function">print_r</span> <span class="token punctuation">（</span><span class="token function"></span></span><mark> <span class="token function">array_keys</span> <span class="token punctuation">（</span> <span class="token variable">$ a</span> <span class="token punctuation">、</span> <span class="token string double-quoted-string">"highlander"</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 delimiter important">？></span>

自分で試してみてください

例3

Strictパラメーターを使用します（false）：

 <span class="token php language-php"><span class="token delimiter important"><？php</span>
<span class="token punctuation">$</span> <span class="token variable">a</span> <span class="token operator">=</span> <span class="token keyword">array</span> <span class="token punctuation">（</span> <span class="token number">10、20、30</span> <span class="token punctuation">、</span> <span class="token string double-quoted-string">"</span> <span class="token number">10</span> <span class="token punctuation">"</span> <span class="token punctuation">）</span> <span class="token punctuation">;</span><span class="token number">​</span>
<span class="token function">print_r</span> <span class="token punctuation">（</span><span class="token function"></span></span><mark> <span class="token function">array_keys</span> <span class="token punctuation">（</span> <span class="token variable">$ a</span> <span class="token punctuation">、</span> <span class="token string double-quoted-string">"10"</span> <span class="token punctuation">、</span> <span class="token constant boolean">false</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 delimiter important">？></span>

自分で試してみてください

例4

Strictパラメーターを使用（TRUE）：

 <span class="token php language-php"><span class="token delimiter important"><？php</span>
<span class="token punctuation">$</span> <span class="token variable">a</span> <span class="token operator">=</span> <span class="token keyword">array</span> <span class="token punctuation">（</span> <span class="token number">10、20、30</span> <span class="token punctuation">、</span> <span class="token string double-quoted-string">"</span> <span class="token number">10</span> <span class="token punctuation">"</span> <span class="token punctuation">）</span> <span class="token punctuation">;</span><span class="token number">​</span>
<span class="token function">print_r</span> <span class="token punctuation">（</span><span class="token function"></span></span><mark> <span class="token function">array_keys</span> <span class="token punctuation">（</span> <span class="token variable">$ a</span> <span class="token punctuation">、</span> <span class="token string double-quoted-string">"10"</span> <span class="token punctuation">、</span> <span class="token constant boolean">true</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 delimiter important">？></span>

自分で試してみてください