title: Pandas counting and summing specific conditions
body: <p>Are there single functions in pandas to perform the equivalents of <a href="http://office.microsoft.com/en-us/excel-help/sumifs-function-HA010047504.aspx" rel="noreferrer">SUMIF</a>, which sums over a specific condition and <a href="http://office.microsoft.com/en-us/excel-help/countifs-function-HA010047494.aspx" rel="noreferrer">COUNTIF</a>, which counts values of specific conditions from Excel?</p>
  
  <p>I know that there are many multiple step functions that can be used for</p>
  
  <p>for example for <code>sumif</code> I can use <code>(df.map(lambda x: condition), or df.size())</code> then use <code>.sum()</code></p>
  
  <p>and for <code>countif</code> I can use <code>(groupby functions</code> and look for my answer or use a filter and the <code>.count())</code> </p>
  
  <p>Is there simple one step process to do these functions where you enter the condition and the data frame and you get the sum or counted results?</p>