product_of_elems = functools.reduce(<spanclass="hljs-keyword">lambda</span> out, x: out * x, <collection>)
list_of_chars = list(<str>)
</code></pre>
<pre><codeclass="python language-python hljs"><bool> = <el><spanclass="hljs-keyword">in</span><collection><spanclass="hljs-comment"># For dictionary it checks if key exists.</span>
index = <list>.index(<el>) <spanclass="hljs-comment"># Returns index of first occurrence or raises ValueError.</span>
<pre><codeclass="python language-python hljs">index = <list>.index(<el>) <spanclass="hljs-comment"># Returns index of first occurrence or raises ValueError.</span>
<list>.insert(index, <el>) <spanclass="hljs-comment"># Inserts item at index and moves the rest to the right.</span>
<el> = <list>.pop([index]) <spanclass="hljs-comment"># Removes and returns item at index or from the end.</span>
<list>.remove(<el>) <spanclass="hljs-comment"># Removes first occurrence of item or raises ValueError.</span>
<list> = <str>.splitlines(keepends=<spanclass="hljs-keyword">False</span>) <spanclass="hljs-comment"># Splits on line breaks. Keeps them if 'keepends'.</span>
<str> = <str>.join(<coll_of_strings>) <spanclass="hljs-comment"># Joins elements using string as separator.</span>
</code></pre>
<pre><codeclass="python language-python hljs"><str> = <str>.replace(old, new [, count]) <spanclass="hljs-comment"># Replaces 'old' with 'new' at most 'count' times.</span>
<pre><codeclass="python language-python hljs"><bool> = <sub_str><spanclass="hljs-keyword">in</span><str><spanclass="hljs-comment"># Checks if string contains a substring.</span>
<bool> = <str>.startswith(<sub_str>) <spanclass="hljs-comment"># Pass tuple of strings for multiple options.</span>
<bool> = <str>.endswith(<sub_str>) <spanclass="hljs-comment"># Pass tuple of strings for multiple options.</span>
<int> = <str>.find(<sub_str>) <spanclass="hljs-comment"># Returns start index of first match or -1.</span>
<int> = <str>.index(<sub_str>) <spanclass="hljs-comment"># Same but raises ValueError.</span>
</code></pre>
<pre><codeclass="python language-python hljs"><bool> = <str>.isnumeric() <spanclass="hljs-comment"># True if str contains only numeric characters.</span>
<pre><codeclass="python language-python hljs"><str> = <str>.replace(old, new [, count]) <spanclass="hljs-comment"># Replaces 'old' with 'new' at most 'count' times.</span>
<bool> = <str>.isnumeric() <spanclass="hljs-comment"># True if str contains only numeric characters.</span>
<list> = textwrap.wrap(<str>, width) <spanclass="hljs-comment"># Nicely breaks string into lines.</span>