Added exercise with warning level

Author: rougier

README.html

@@ -233,15 +233,26 @@ <h2 class="subtitle" id="a-joint-effort-of-the-numpy-community">A joint effort o
 <span class="keyword">print</span><span class="punctuation">(</span><span class="name">np</span><span class="operator">.</span><span class="name">intersect1d</span><span class="punctuation">(</span><span class="name">Z1</span><span class="punctuation">,</span><span class="name">Z2</span><span class="punctuation">))</span>
 </pre>
 </li>
+<li><p class="first">How to ignore all numpy warnings (not recommended)? (★☆☆)</p>
+<pre class="code python literal-block">
+<span class="comment single"># Suicide mode on</span>
+<span class="name">defaults</span> <span class="operator">=</span> <span class="name">np</span><span class="operator">.</span><span class="name">seterr</span><span class="punctuation">(</span><span class="name builtin">all</span><span class="operator">=</span><span class="literal string double">&quot;ignore&quot;</span><span class="punctuation">)</span>
+<span class="name">Z</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">1</span><span class="punctuation">)</span><span class="operator">/</span><span class="literal number integer">0</span>
+
+<span class="comment single"># Back to sanity</span>
+<span class="name">np</span><span class="operator">.</span><span class="name">seterr</span><span class="punctuation">(</span><span class="operator">**</span><span class="name">defaults</span><span class="punctuation">)</span>
+</pre>
+</li>
 <li><p class="first">Is the following expressions true? (★☆☆)</p>
 <pre class="code python literal-block">
 <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>
+<li><p class="first">How to get the dates of yesterday, today and tomorrow? (★☆☆)</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>
+<span class="name">yesterday</span> <span class="operator">=</span> <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="operator">-</span> <span class="name">np</span><span class="operator">.</span><span class="name">timedelta64</span><span class="punctuation">(</span><span class="literal number integer">1</span><span class="punctuation">,</span> <span class="literal string single">'D'</span><span class="punctuation">)</span>
+<span class="name">today</span>     <span class="operator">=</span> <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">tomorrow</span>  <span class="operator">=</span> <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="operator">+</span> <span class="name">np</span><span class="operator">.</span><span class="name">timedelta64</span><span class="punctuation">(</span><span class="literal number integer">1</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>

README.rst

@@ -278,18 +278,32 @@ Thanks to Michiaki Ariga, there is now a
       Z2 = np.random.randint(0,10,10)
       print(np.intersect1d(Z1,Z2))
 
+#. How to ignore all numpy warnings (not recommended)? (★☆☆)
+   
+   .. code-block:: python
+
+      # Suicide mode on
+      defaults = np.seterr(all="ignore")
+      Z = np.ones(1)/0
+
+      # Back to sanity
+      np.seterr(**defaults)
+      
+   
 #. Is the following expressions true? (★☆☆)
 
    .. code-block:: python
 
       np.sqrt(-1) == np.emath.sqrt(-1)
 
-#. How to get the current date ? (★☆☆) 
+#. How to get the dates of yesterday, today and tomorrow? (★☆☆) 
 
    .. code-block:: python
 
-      np.datetime64('today', 'D')
-      np.datetime64('now', 'D')
+      yesterday = np.datetime64('today', 'D') - np.timedelta64(1, 'D')
+      today     = np.datetime64('today', 'D')
+      tomorrow  = np.datetime64('today', 'D') + np.timedelta64(1, 'D')
+
       
 #. How to get all the dates corresponding to the month of July 2016? (★★☆)