Added two datetime exercises

This commit is contained in:
Nicolas P. Rougier
2016-07-14 19:58:32 -05:00
parent e8dd40096d
commit 503be76295
2 changed files with 27 additions and 0 deletions

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@@ -238,6 +238,18 @@ python -c <span class="literal string double">&quot;import numpy; numpy.info(num
<span class="name">np</span><span class="operator">.</span><span class="name">sqrt</span><span class="punctuation">(</span><span class="operator">-</span><span class="literal number integer">1</span><span class="punctuation">)</span> <span class="operator">==</span> <span class="name">np</span><span class="operator">.</span><span class="name">emath</span><span class="operator">.</span><span class="name">sqrt</span><span class="punctuation">(</span><span class="operator">-</span><span class="literal number integer">1</span><span class="punctuation">)</span>
</pre>
</li>
<li><p class="first">How to get the current date ? (★☆☆)</p>
<pre class="code python literal-block">
<span class="name">np</span><span class="operator">.</span><span class="name">datetime64</span><span class="punctuation">(</span><span class="literal string single">'today'</span><span class="punctuation">,</span> <span class="literal string single">'D'</span><span class="punctuation">)</span>
<span class="name">np</span><span class="operator">.</span><span class="name">datetime64</span><span class="punctuation">(</span><span class="literal string single">'now'</span><span class="punctuation">,</span> <span class="literal string single">'D'</span><span class="punctuation">)</span>
</pre>
</li>
<li><p class="first">How to get all the dates corresponding to the month of July 2016? (★★☆)</p>
<pre class="code python literal-block">
<span class="name">Z</span> <span class="operator">=</span> <span class="name">np</span><span class="operator">.</span><span class="name">arange</span><span class="punctuation">(</span><span class="literal string single">'2016-07'</span><span class="punctuation">,</span> <span class="literal string single">'2016-08'</span><span class="punctuation">,</span> <span class="name">dtype</span><span class="operator">=</span><span class="literal string single">'datetime64[D]'</span><span class="punctuation">)</span>
<span class="keyword">print</span><span class="punctuation">(</span><span class="name">Z</span><span class="punctuation">)</span>
</pre>
</li>
<li><p class="first">How to compute ((A+B)*(-A/2)) in place (without copy)? (★★☆)</p>
<pre class="code python literal-block">
<span class="name">A</span> <span class="operator">=</span> <span class="name">np</span><span class="operator">.</span><span class="name">ones</span><span class="punctuation">(</span><span class="literal number integer">3</span><span class="punctuation">)</span><span class="operator">*</span><span class="literal number integer">1</span>

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@@ -284,6 +284,21 @@ Thanks to Michiaki Ariga, there is now a
np.sqrt(-1) == np.emath.sqrt(-1)
#. How to get the current date ? (★☆☆)
.. code-block:: python
np.datetime64('today', 'D')
np.datetime64('now', 'D')
#. How to get all the dates corresponding to the month of July 2016? (★★☆)
.. code-block:: python
Z = np.arange('2016-07', '2016-08', dtype='datetime64[D]')
print(Z)
#. How to compute ((A+B)*(-A/2)) in place (without copy)? (★★☆)
.. code-block:: python