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substr

返回字符串的一部分
名稱:substr
分類:字符串
所屬語言:php
一句話介紹:返回字符串的一部分。

實例

例子1

從字符串中返回"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>

親自試一試

例子2

使用帶有不同正負數的start參數:

 <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>

親自試一試

例子3

使用帶有不同正負數的startlength參數:

 <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>

親自試一試

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