<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> <title>api example code: histogram_demo.py — Matplotlib v1.1.1 documentation</title> <link rel="stylesheet" href="../../_static/mpl.css" type="text/css" /> <link rel="stylesheet" href="../../_static/pygments.css" type="text/css" /> <script type="text/javascript"> var DOCUMENTATION_OPTIONS = { URL_ROOT: '../../', VERSION: '1.1.1', COLLAPSE_INDEX: false, FILE_SUFFIX: '.html', HAS_SOURCE: true }; </script> <script type="text/javascript" src="../../_static/jquery.js"></script> <script type="text/javascript" src="../../_static/underscore.js"></script> <script type="text/javascript" src="../../_static/doctools.js"></script> <link rel="search" type="application/opensearchdescription+xml" title="Search within Matplotlib v1.1.1 documentation" href="../../_static/opensearch.xml"/> <link rel="top" title="Matplotlib v1.1.1 documentation" href="../../index.html" /> </head> <body> <!-- Piwik --> <script type="text/javascript"> if ("matplotlib.sourceforge.net" == document.location.hostname || "matplotlib.sf.net" == document.location.hostname) { var pkBaseURL = (("https:" == document.location.protocol) ? "https://apps.sourceforge.net/piwik/matplotlib/" : "http://apps.sourceforge.net/piwik/matplotlib/"); document.write(unescape("%3Cscript src='" + pkBaseURL + "piwik.js' type='text/javascript'%3E%3C/script%3E")); } </script> <script type="text/javascript"> if ("matplotlib.sourceforge.net" == document.location.hostname || "matplotlib.sf.net" == document.location.hostname) { piwik_action_name = ''; piwik_idsite = 1; piwik_url = pkBaseURL + "piwik.php"; piwik_log(piwik_action_name, piwik_idsite, piwik_url); document.write(unescape('%3Cobject%3E%3Cnoscript%3E%3Cp%3E%3Cimg src="http://apps.sourceforge.net/piwik/matplotlib/piwik.php?idsite=1" alt="piwik"/%3E%3C/p%3E%3C/noscript%3E%3C/object%3E')); } </script> <!-- End Piwik Tag --> <link rel="shortcut icon" href="_static/favicon.ico"> <div style="background-color: white; text-align: left; padding: 10px 10px 15px 15px"> <a href="../../index.html"><img src="../../_static/logo2.png" border="0" alt="matplotlib"/></a> </div> <div class="related"> <h3>Navigation</h3> <ul> <li class="right" style="margin-right: 10px"> <a href="../../genindex.html" title="General Index" accesskey="I">index</a></li> <li class="right" > <a href="../../py-modindex.html" title="Python Module Index" >modules</a> |</li> <li><a href="../../index.html">home</a>| </li> <li><a href="../../search.html">search</a>| </li> <li><a href="../index.html">examples</a>| </li> <li><a href="../../gallery.html">gallery</a>| </li> <li><a href="../../contents.html">docs</a> »</li> </ul> </div> <div class="sphinxsidebar"> <div class="sphinxsidebarwrapper"> <h3>This Page</h3> <ul class="this-page-menu"> <li><a href="../../_sources/examples/api/histogram_demo.txt" rel="nofollow">Show Source</a></li> </ul> <div id="searchbox" style="display: none"> <h3>Quick search</h3> <form class="search" action="../../search.html" method="get"> <input type="text" name="q" size="18" /> <input type="submit" value="Go" /> <input type="hidden" name="check_keywords" value="yes" /> <input type="hidden" name="area" value="default" /> </form> <p class="searchtip" style="font-size: 90%"> Enter search terms or a module, class or function name. </p> </div> <script type="text/javascript">$('#searchbox').show(0);</script> </div> </div> <div class="document"> <div class="documentwrapper"> <div class="bodywrapper"> <div class="body"> <div class="section" id="api-example-code-histogram-demo-py"> <span id="api-histogram-demo"></span><h1>api example code: histogram_demo.py<a class="headerlink" href="#api-example-code-histogram-demo-py" title="Permalink to this headline">ΒΆ</a></h1> <p>(<a class="reference external" href="../../mpl_examples/api/histogram_demo.py">Source code</a>, <a class="reference external" href="../../mpl_examples/api/histogram_demo.png">png</a>, <a class="reference external" href="../../mpl_examples/api/histogram_demo.hires.png">hires.png</a>, <a class="reference external" href="../../mpl_examples/api/histogram_demo.pdf">pdf</a>)</p> <div class="figure"> <img alt="../../_images/histogram_demo1.png" src="../../_images/histogram_demo1.png" /> </div> <div class="highlight-python"><div class="highlight"><pre><span class="sd">"""</span> <span class="sd">Make a histogram of normally distributed random numbers and plot the</span> <span class="sd">analytic PDF over it</span> <span class="sd">"""</span> <span class="kn">import</span> <span class="nn">numpy</span> <span class="kn">as</span> <span class="nn">np</span> <span class="kn">import</span> <span class="nn">matplotlib.pyplot</span> <span class="kn">as</span> <span class="nn">plt</span> <span class="kn">import</span> <span class="nn">matplotlib.mlab</span> <span class="kn">as</span> <span class="nn">mlab</span> <span class="n">mu</span><span class="p">,</span> <span class="n">sigma</span> <span class="o">=</span> <span class="mi">100</span><span class="p">,</span> <span class="mi">15</span> <span class="n">x</span> <span class="o">=</span> <span class="n">mu</span> <span class="o">+</span> <span class="n">sigma</span> <span class="o">*</span> <span class="n">np</span><span class="o">.</span><span class="n">random</span><span class="o">.</span><span class="n">randn</span><span class="p">(</span><span class="mi">10000</span><span class="p">)</span> <span class="n">fig</span> <span class="o">=</span> <span class="n">plt</span><span class="o">.</span><span class="n">figure</span><span class="p">()</span> <span class="n">ax</span> <span class="o">=</span> <span class="n">fig</span><span class="o">.</span><span class="n">add_subplot</span><span class="p">(</span><span class="mi">111</span><span class="p">)</span> <span class="c"># the histogram of the data</span> <span class="n">n</span><span class="p">,</span> <span class="n">bins</span><span class="p">,</span> <span class="n">patches</span> <span class="o">=</span> <span class="n">ax</span><span class="o">.</span><span class="n">hist</span><span class="p">(</span><span class="n">x</span><span class="p">,</span> <span class="mi">50</span><span class="p">,</span> <span class="n">normed</span><span class="o">=</span><span class="mi">1</span><span class="p">,</span> <span class="n">facecolor</span><span class="o">=</span><span class="s">'green'</span><span class="p">,</span> <span class="n">alpha</span><span class="o">=</span><span class="mf">0.75</span><span class="p">)</span> <span class="c"># hist uses np.histogram under the hood to create 'n' and 'bins'.</span> <span class="c"># np.histogram returns the bin edges, so there will be 50 probability</span> <span class="c"># density values in n, 51 bin edges in bins and 50 patches. To get</span> <span class="c"># everything lined up, we'll compute the bin centers</span> <span class="n">bincenters</span> <span class="o">=</span> <span class="mf">0.5</span><span class="o">*</span><span class="p">(</span><span class="n">bins</span><span class="p">[</span><span class="mi">1</span><span class="p">:]</span><span class="o">+</span><span class="n">bins</span><span class="p">[:</span><span class="o">-</span><span class="mi">1</span><span class="p">])</span> <span class="c"># add a 'best fit' line for the normal PDF</span> <span class="n">y</span> <span class="o">=</span> <span class="n">mlab</span><span class="o">.</span><span class="n">normpdf</span><span class="p">(</span> <span class="n">bincenters</span><span class="p">,</span> <span class="n">mu</span><span class="p">,</span> <span class="n">sigma</span><span class="p">)</span> <span class="n">l</span> <span class="o">=</span> <span class="n">ax</span><span class="o">.</span><span class="n">plot</span><span class="p">(</span><span class="n">bincenters</span><span class="p">,</span> <span class="n">y</span><span class="p">,</span> <span class="s">'r--'</span><span class="p">,</span> <span class="n">linewidth</span><span class="o">=</span><span class="mi">1</span><span class="p">)</span> <span class="n">ax</span><span class="o">.</span><span class="n">set_xlabel</span><span class="p">(</span><span class="s">'Smarts'</span><span class="p">)</span> <span class="n">ax</span><span class="o">.</span><span class="n">set_ylabel</span><span class="p">(</span><span class="s">'Probability'</span><span class="p">)</span> <span class="c">#ax.set_title(r'$\mathrm{Histogram\ of\ IQ:}\ \mu=100,\ \sigma=15$')</span> <span class="n">ax</span><span class="o">.</span><span class="n">set_xlim</span><span class="p">(</span><span class="mi">40</span><span class="p">,</span> <span class="mi">160</span><span class="p">)</span> <span class="n">ax</span><span class="o">.</span><span class="n">set_ylim</span><span class="p">(</span><span class="mi">0</span><span class="p">,</span> <span class="mf">0.03</span><span class="p">)</span> <span class="n">ax</span><span class="o">.</span><span class="n">grid</span><span class="p">(</span><span class="bp">True</span><span class="p">)</span> <span class="n">plt</span><span class="o">.</span><span class="n">show</span><span class="p">()</span> </pre></div> </div> <p>Keywords: python, matplotlib, pylab, example, codex (see <a class="reference internal" href="../../faq/howto_faq.html#how-to-search-examples"><em>Search examples</em></a>)</p> </div> </div> </div> </div> <div class="clearer"></div> </div> <div class="related"> <h3>Navigation</h3> <ul> <li class="right" style="margin-right: 10px"> <a href="../../genindex.html" title="General Index" >index</a></li> <li class="right" > <a href="../../py-modindex.html" title="Python Module Index" >modules</a> |</li> <li><a href="../../index.html">home</a>| </li> <li><a href="../../search.html">search</a>| </li> <li><a href="../index.html">examples</a>| </li> <li><a href="../../gallery.html">gallery</a>| </li> <li><a href="../../contents.html">docs</a> »</li> </ul> </div> <div class="footer"> © Copyright 2008, John Hunter, Darren Dale, Michael Droettboom. Last updated on Oct 04, 2012. Created using <a href="http://sphinx.pocoo.org/">Sphinx</a> 1.0.7. </div> </body> </html>