<num> = sum(<collection>) <spanclass="hljs-comment"># Also math.prod(<collection>).</span>
</code></pre></div>
<div><h3id="math">Math</h3><pre><codeclass="python language-python hljs"><spanclass="hljs-keyword">from</span> math <spanclass="hljs-keyword">import</span>e, pi, inf, nan, isnan <spanclass="hljs-comment"># `inf*0` and `nan+1` return nan.</span>
<div><h3id="math">Math</h3><pre><codeclass="python language-python hljs"><spanclass="hljs-keyword">from</span> math <spanclass="hljs-keyword">import</span> pi, inf, nan, isnan<spanclass="hljs-comment"># `inf*0` and `nan+1` return nan.</span>
<spanclass="hljs-keyword">from</span> math <spanclass="hljs-keyword">import</span> sqrt, factorial <spanclass="hljs-comment"># `sqrt(-1)` raises ValueError.</span>
<spanclass="hljs-keyword">from</span> math <spanclass="hljs-keyword">import</span> sin, cos, tan <spanclass="hljs-comment"># Also: asin, degrees, radians.</span>
<spanclass="hljs-keyword">from</span> math <spanclass="hljs-keyword">import</span> log, log10, log2 <spanclass="hljs-comment"># Log accepts base as second arg.</span>
<pre><codeclass="python language-python hljs"><spanclass="hljs-meta">>>></span>list(it.combinations(<spanclass="hljs-string">'abc'</span>, <spanclass="hljs-number">2</span>)) <spanclass="hljs-comment"># a b c</span>
[(<spanclass="hljs-string">'a'</span>, <spanclass="hljs-string">'b'</span>), (<spanclass="hljs-string">'a'</span>, <spanclass="hljs-string">'c'</span>), <spanclass="hljs-comment"># a . x x</span>
(<spanclass="hljs-string">'b'</span>, <spanclass="hljs-string">'c'</span>),<spanclass="hljs-comment"># b . . x</span>
(<spanclass="hljs-string">'b'</span>, <spanclass="hljs-string">'c'</span>)<spanclass="hljs-comment"># b . . x</span>
] <spanclass="hljs-comment"># c . . .</span>
</code></pre>
<div><h2id="datetime"><ahref="#datetime"name="datetime">#</a>Datetime</h2><p><strong>Provides 'date', 'time', 'datetime' and 'timedelta' classes. All are immutable and hashable.</strong></p><pre><codeclass="python language-python hljs"><spanclass="hljs-comment"># $ pip3 install python-dateutil</span>