<1d/2d_a> = <2d_array>[<2d/1d_bools>] <spanclass="hljs-comment"># 1d_bools must have size of a column.</span>
</code></pre>
<ul>
<li><strong>Indexes should not be tuples because Python converts <codeclass="python hljs"><spanclass="hljs-string">'obj[i, j]'</span></code> to <codeclass="python hljs"><spanclass="hljs-string">'obj[(i, j)]'</span></code>.</strong></li>
<li><strong>Indexes should not be tuples because Python converts <codeclass="python hljs"><spanclass="hljs-string">'obj[i, j]'</span></code> to <codeclass="python hljs"><spanclass="hljs-string">'obj[(i, j)]'</span></code>!</strong></li>
<li><strong>Any value that is broadcastable to the indexed shape can be assigned to the selection.</strong></li>
</ul>
<div><h3id="broadcasting">Broadcasting</h3><p><strong>Set of rules by which NumPy functions operate on arrays of different sizes and/or dimensions.</strong></p><pre><codeclass="python language-python hljs">left = [[<spanclass="hljs-number">0.1</span>], [<spanclass="hljs-number">0.6</span>], [<spanclass="hljs-number">0.8</span>]] <spanclass="hljs-comment"># Shape: (3, 1)</span>
<li><strong>Methods ffill(), interpolate() and fillna() accept argument 'inplace' that defaults to False.</strong></li>
<li><strong>Keys/indexes/bools can't be tuples because <codeclass="python hljs"><spanclass="hljs-string">'obj[x, y]'</span></code> is converted to <codeclass="python hljs"><spanclass="hljs-string">'obj[(x, y)]'</span></code>!</strong></li>
<li><strong>Methods ffill(), interpolate(), fillna() and dropna() accept <codeclass="python hljs"><spanclass="hljs-string">'inplace=True'</span></code>.</strong></li>
<li><strong>Last result has a hierarchical index. Use <codeclass="python hljs"><spanclass="hljs-string">'<Sr>[key_1, key_2]'</span></code> to get its values.</strong></li>
<li><strong>Keys/indexes/bools can't be tuples because <codeclass="python hljs"><spanclass="hljs-string">'obj[x, y]'</span></code> is converted to <codeclass="python hljs"><spanclass="hljs-string">'obj[(x, y)]'</span></code>.</strong></li>
</ul>
<div><h3id="dataframe">DataFrame</h3><p><strong>Table with labeled rows and columns.</strong></p><pre><codeclass="python language-python hljs"><spanclass="hljs-meta">>>></span>pd.DataFrame([[<spanclass="hljs-number">1</span>, <spanclass="hljs-number">2</span>], [<spanclass="hljs-number">3</span>, <spanclass="hljs-number">4</span>]], index=[<spanclass="hljs-string">'a'</span>, <spanclass="hljs-string">'b'</span>], columns=[<spanclass="hljs-string">'x'</span>, <spanclass="hljs-string">'y'</span>])