title: Getting IndexError: only integers, slices (`:`), ellipsis (`...`), numpy.newaxis (`None`) and integer or boolean arrays are valid indices
body: <p>I'm getting this index error when I run this function. This function finds the average rent  prices of a zipcode of a city. I have a dictionary of cities called city with zipcode as the key and city name as the value. There are multiple zipcodes for some cities and arrRent is a array with lists of rents of houses of the city and I want to find the average rent price.</p>
  
  <pre><code>def meanPrice(self, city):
      total = 0
      cityLoc = 0
      for keys, cities in self.city.items():
          if self.city[keys] == city:
              for i in self.arrRent[cityLoc]:
                  total += int(self.arrRent[cityLoc][i])
              mean = total / i
              print(total / i)
          else:
              cityLoc += 1
  </code></pre>
  
  <p>Here's a snippet of the dictionary:</p>
  
  <pre><code>{'95129': 'San Jose'}
  {'95128': 'San Jose'}
  {'95054': 'Santa Clara'}
  {'95051': 'Santa Clara'}
  {'95050': 'Santa Clara'}
  </code></pre>
  
  <p>and here's a snippet of the array:</p>
  
  <pre><code>[['2659' '2623.5' '2749.5' '2826.5' '2775' '2795' '2810' '2845' '2827'
    '2847' '2854' '2897.5' '2905' '2925' '2902.5' '2869.5']
  
  ['3342.5' '3386' '3385' '3353' '3300' '3190' '3087.5' '3092' '3170'
    '3225' '3340' '3315' '3396' '3470' '3480' '3380']
  
  ['2996' '2989' '2953' '2950' '2884.5' '2829' '2785' '2908' '2850' '2761'
    '2997.5' '3020' '2952' '2997.5' '2952' '2923.5']
  
   ['2804.5' '2850.5' '2850' '2850' '2867' '2940' '2905' '2945' '2938'
    '2860' '2884' '2946' '2938' '2986.5' '2931.5' '3032.5']
  
   ['2800' '3074' '2950' '2850' '2850' '2875' '2757' '2716' '2738.5' '2696'
    '2809' '2891' '3000' '2960' '2950' '2831']]
  </code></pre>