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将数组的内部指针倒回一位
简体中文
简体中文
输出数组中的当前元素、下一个元素和上一个元素的值：
<span class="token php language-php"><span class="token delimiter important"><?php</span> <span class="token variable">$people</span> <span class="token operator">=</span> <span class="token keyword">array</span><span class="token punctuation">(</span><span class="token string double-quoted-string">"Bill"</span><span class="token punctuation">,</span> <span class="token string double-quoted-string">"Steve"</span><span class="token punctuation">,</span> <span class="token string double-quoted-string">"Mark"</span><span class="token punctuation">,</span> <span class="token string double-quoted-string">"David"</span><span class="token punctuation">)</span><span class="token punctuation">;</span> <span class="token keyword">echo</span> <span class="token function">current</span><span class="token punctuation">(</span><span class="token variable">$people</span><span class="token punctuation">)</span> <span class="token operator">.</span> <span class="token string double-quoted-string">"<br>"</span><span class="token punctuation">;</span> <span class="token keyword">echo</span> <span class="token function">next</span><span class="token punctuation">(</span><span class="token variable">$people</span><span class="token punctuation">)</span> <span class="token operator">.</span> <span class="token string double-quoted-string">"<br>"</span><span class="token punctuation">;</span> <span class="token keyword">echo</span> <span class="token function"></span><mark><span class="token function">prev</span><span class="token punctuation">(</span><span class="token variable">$people</span><span class="token punctuation">)</span></mark><span class="token punctuation"></span><span class="token punctuation">;</span> <span class="token delimiter important">?></span></span>
演示所有相关的方法：
<span class="token php language-php"><span class="token delimiter important"><?php</span> <span class="token variable">$people</span> <span class="token operator">=</span> <span class="token keyword">array</span><span class="token punctuation">(</span><span class="token string double-quoted-string">"Bill"</span><span class="token punctuation">,</span> <span class="token string double-quoted-string">"Steve"</span><span class="token punctuation">,</span> <span class="token string double-quoted-string">"Mark"</span><span class="token punctuation">,</span> <span class="token string double-quoted-string">"David"</span><span class="token punctuation">)</span><span class="token punctuation">;</span> <span class="token keyword">echo</span> <span class="token function">current</span><span class="token punctuation">(</span><span class="token variable">$people</span><span class="token punctuation">)</span> <span class="token operator">.</span> <span class="token string double-quoted-string">"<br>"</span><span class="token punctuation">;</span> <span class="token comment">// 当前元素是 Bill</span> <span class="token keyword">echo</span> <span class="token function">next</span><span class="token punctuation">(</span><span class="token variable">$people</span><span class="token punctuation">)</span> <span class="token operator">.</span> <span class="token string double-quoted-string">"<br>"</span><span class="token punctuation">;</span> <span class="token comment">// Bill 的下一个元素是 Steve</span> <span class="token keyword">echo</span> <span class="token function">current</span><span class="token punctuation">(</span><span class="token variable">$people</span><span class="token punctuation">)</span> <span class="token operator">.</span> <span class="token string double-quoted-string">"<br>"</span><span class="token punctuation">;</span> <span class="token comment">// 现在当前元素是 Steve</span> <span class="token keyword">echo</span> <span class="token function"></span><mark><span class="token function">prev</span><span class="token punctuation">(</span><span class="token variable">$people</span><span class="token punctuation">)</span></mark><span class="token punctuation"></span> <span class="token operator">.</span> <span class="token string double-quoted-string">"<br>"</span><span class="token punctuation">;</span> <span class="token comment">// Steve 的上一个元素是 Bill</span> <span class="token keyword">echo</span> <span class="token function">end</span><span class="token punctuation">(</span><span class="token variable">$people</span><span class="token punctuation">)</span> <span class="token operator">.</span> <span class="token string double-quoted-string">"<br>"</span><span class="token punctuation">;</span> <span class="token comment">// 最后一个元素是 David</span> <span class="token keyword">echo</span> <span class="token function"></span><mark><span class="token function">prev</span><span class="token punctuation">(</span><span class="token variable">$people</span><span class="token punctuation">)</span></mark><span class="token punctuation"></span> <span class="token operator">.</span> <span class="token string double-quoted-string">"<br>"</span><span class="token punctuation">;</span> <span class="token comment">// David 之前的元素是 Mark</span> <span class="token keyword">echo</span> <span class="token function">current</span><span class="token punctuation">(</span><span class="token variable">$people</span><span class="token punctuation">)</span> <span class="token operator">.</span> <span class="token string double-quoted-string">"<br>"</span><span class="token punctuation">;</span> <span class="token comment">// 目前的当前元素是 Mark</span> <span class="token keyword">echo</span> <span class="token function">reset</span><span class="token punctuation">(</span><span class="token variable">$people</span><span class="token punctuation">)</span> <span class="token operator">.</span> <span class="token string double-quoted-string">"<br>"</span><span class="token punctuation">;</span> <span class="token comment">// 把内部指针移动到数组的首个元素，即 Bill</span> <span class="token keyword">echo</span> <span class="token function">next</span><span class="token punctuation">(</span><span class="token variable">$people</span><span class="token punctuation">)</span> <span class="token operator">.</span> <span class="token string double-quoted-string">"<br>"</span><span class="token punctuation">;</span> <span class="token comment">// Bill 的下一个元素是 Steve</span> <span class="token function">print_r</span> <span class="token punctuation">(</span><span class="token function">each</span><span class="token punctuation">(</span><span class="token variable">$people</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span> <span class="token comment">// 返回当前元素的键名和键值（目前是 Steve），并向前移动内部指针</span> <span class="token delimiter important">?></span></span>
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