substr

名称:substr

分类:字符串

所属语言:php

一句话介绍:返回字符串的一部分。

实例

例子 1

从字符串中返回 "world"：

<span class="token php language-php"><span class="token delimiter important"><?php</span>
<span class="token keyword">echo</span> <span class="token function">substr</span><span class="token punctuation">(</span><span class="token string double-quoted-string">"Hello world"</span><span class="token punctuation">,</span><span class="token number">6</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token delimiter important">?></span></span>

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例子 2

使用带有不同正负数的 start 参数：

<span class="token php language-php"><span class="token delimiter important"><?php</span>
<span class="token keyword">echo</span> <span class="token function">substr</span><span class="token punctuation">(</span><span class="token string double-quoted-string">"Hello world"</span><span class="token punctuation">,</span><span class="token number">10</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">substr</span><span class="token punctuation">(</span><span class="token string double-quoted-string">"Hello world"</span><span class="token punctuation">,</span><span class="token number">1</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">substr</span><span class="token punctuation">(</span><span class="token string double-quoted-string">"Hello world"</span><span class="token punctuation">,</span><span class="token number">3</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">substr</span><span class="token punctuation">(</span><span class="token string double-quoted-string">"Hello world"</span><span class="token punctuation">,</span><span class="token number">7</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">substr</span><span class="token punctuation">(</span><span class="token string double-quoted-string">"Hello world"</span><span class="token punctuation">,</span><span class="token operator">-</span><span class="token number">1</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">substr</span><span class="token punctuation">(</span><span class="token string double-quoted-string">"Hello world"</span><span class="token punctuation">,</span><span class="token operator">-</span><span class="token number">10</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">substr</span><span class="token punctuation">(</span><span class="token string double-quoted-string">"Hello world"</span><span class="token punctuation">,</span><span class="token operator">-</span><span class="token number">8</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">substr</span><span class="token punctuation">(</span><span class="token string double-quoted-string">"Hello world"</span><span class="token punctuation">,</span><span class="token operator">-</span><span class="token number">4</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 delimiter important">?></span></span>

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例子 3

使用带有不同正负数的 start 和 length 参数：

<span class="token php language-php"><span class="token delimiter important"><?php</span>
<span class="token keyword">echo</span> <span class="token function">substr</span><span class="token punctuation">(</span><span class="token string double-quoted-string">"Hello world"</span><span class="token punctuation">,</span><span class="token number">0</span><span class="token punctuation">,</span><span class="token number">10</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">substr</span><span class="token punctuation">(</span><span class="token string double-quoted-string">"Hello world"</span><span class="token punctuation">,</span><span class="token number">1</span><span class="token punctuation">,</span><span class="token number">8</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">substr</span><span class="token punctuation">(</span><span class="token string double-quoted-string">"Hello world"</span><span class="token punctuation">,</span><span class="token number">0</span><span class="token punctuation">,</span><span class="token number">5</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">substr</span><span class="token punctuation">(</span><span class="token string double-quoted-string">"Hello world"</span><span class="token punctuation">,</span><span class="token number">6</span><span class="token punctuation">,</span><span class="token number">6</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">substr</span><span class="token punctuation">(</span><span class="token string double-quoted-string">"Hello world"</span><span class="token punctuation">,</span><span class="token number">0</span><span class="token punctuation">,</span><span class="token operator">-</span><span class="token number">1</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">substr</span><span class="token punctuation">(</span><span class="token string double-quoted-string">"Hello world"</span><span class="token punctuation">,</span><span class="token operator">-</span><span class="token number">10</span><span class="token punctuation">,</span><span class="token operator">-</span><span class="token number">2</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">substr</span><span class="token punctuation">(</span><span class="token string double-quoted-string">"Hello world"</span><span class="token punctuation">,</span><span class="token number">0</span><span class="token punctuation">,</span><span class="token operator">-</span><span class="token number">6</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">substr</span><span class="token punctuation">(</span><span class="token string double-quoted-string">"Hello world"</span><span class="token punctuation">,</span><span class="token operator">-</span><span class="token number">2</span><span class="token operator">-</span><span class="token number">3</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 delimiter important">?></span></span>

亲自试一试