find()从左向右寻找子序列的位置，如存在多个相同子序列只返回第一个查找到的位置，如果子序列不存在返回-1。
rfind()从右向左寻找子序列的位置，如存在多个相同子序列只返回第一个查找到的位置，如果子序列不存在返回-1，其实可以理解为从左向右找到最后一个查找到的位置。
index()从左向右寻找子序列的位置，如果子序列不存在报错，所以一般我们用find()更好一些。
rindex()从右向左寻找子序列的位置，如果子序列不存在报错。
1.find，rfind
<code class="prism language-python">a <span class="token operator">=</span> <span class="token string">"hello world"</span> a1 <span class="token operator">=</span> a<span class="token punctuation">.</span>find<span class="token punctuation">(</span><span class="token string">"l"</span><span class="token punctuation">)</span> a2 <span class="token operator">=</span> a<span class="token punctuation">.</span>rfind<span class="token punctuation">(</span><span class="token string">"v"</span><span class="token punctuation">)</span> <span class="token keyword">print</span><span class="token punctuation">(</span>a1<span class="token punctuation">)</span> <span class="token keyword">print</span><span class="token punctuation">(</span>a2<span class="token punctuation">)</span> </code>
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输出：
<code class="prism language-python"><span class="token number">2</span> <span class="token operator">-</span><span class="token number">1</span> </code>
2.index，rindex
<code class="prism language-python">b <span class="token operator">=</span> <span class="token string">"hello world"</span> b1 <span class="token operator">=</span> b<span class="token punctuation">.</span>index<span class="token punctuation">(</span><span class="token string">"l"</span><span class="token punctuation">)</span> b2 <span class="token operator">=</span> b<span class="token punctuation">.</span>rindex<span class="token punctuation">(</span><span class="token string">"v"</span><span class="token punctuation">)</span> <span class="token keyword">print</span><span class="token punctuation">(</span>b1<span class="token punctuation">)</span> <span class="token keyword">print</span><span class="token punctuation">(</span>b2<span class="token punctuation">)</span> </code>
输出：
<code class="prism language-python"><span class="token number">2</span>
Traceback <span class="token punctuation">(</span>most recent call last<span class="token punctuation">)</span><span class="token punctuation">:</span>
File <span class="token string">"test.py"</span><span class="token punctuation">,</span> line <span class="token number">3</span><span class="token punctuation">,</span> <span class="token keyword">in</span> <span class="token operator"><</span>module<span class="token operator">></span>
b2 <span class="token operator">=</span> b<span class="token punctuation">.</span>index<span class="token punctuation">(</span><span class="token string">"v"</span><span class="token punctuation">)</span>
ValueError<span class="token punctuation">:</span> substring <span class="token operator">not</span> found
</code>
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转载请注明原文链接：python中对于find，rfind，index，rindex的见解
转载请注明原文链接：python中对于find，rfind，index，rindex的见解
