title: Recursively select elements in numpy array
body: <p>I have a text file containing latitude and temperature values for points around the globe. I would like to take the average of all the temperature points between a specified latitude interval (i.e. every degree, from the South to the North Pole). This is the code I have so far:</p>
  
  <pre><code>data_in = genfromtxt('temperatures.txt', usecols = (0,1)) 
  lat = data_in[:,0]
  temp = data_in[:,1]
  
  in_1N = np.where((lat&gt;=0) &amp; (lat&lt;=1)) # outputs an array of indexes for all latitudes between 0°-1° North
  temp_1N = temp[in_1N] # outputs an array of temperature values between 0°-1° North
  avg_1N = np.nanmean(temp_1N) # works out the average of temperatures between 0°-1° North
  
  plt.scatter(1, avg_1N) # plots the average temperature against the latitude interval
  plt.show()
  </code></pre>
  
  <p>How could I improve this code, so it can be implemented 180 times to cover the Earth between -90°S and 90°N?
  Thanks</p>