title: Load only up to a number of lines when loading a csv file in numpy
body: <p>When working with large datasets, I often want to test my code with very few samples. This allows me to spot bugs before investing a long time in calculations.</p>
  
  <p>One of the time consuming steps is often reading the data, so it's nice that Pandas lets me specify <a href="http://pandas.pydata.org/pandas-docs/stable/generated/pandas.read_csv.html#pandas.read_csv" rel="nofollow">nrows</a> to read the file up to a certain line, then stop. I don't care about accuracy, but about code bugs. </p>
  
  <p>I don't seem to find a similar functionlity when using numpy directly, either with <a href="http://docs.scipy.org/doc/numpy/reference/generated/numpy.genfromtxt.html" rel="nofollow">getfromtxt</a> or <a href="http://docs.scipy.org/doc/numpy/reference/generated/numpy.loadtxt.html#numpy.loadtxt" rel="nofollow">loadtxt</a>. Am I overseeing something? I'll go ahead and look into it myself if it's not available, but I thought I'd check with you guys first. Thanks! </p>