title: new column with coordinates using geopy pandas
body: <p>I have a df:</p>
  
  <pre><code>import pandas as pd
  import numpy as np
  import datetime as DT
  import hmac
  from geopy.geocoders import Nominatim
  from geopy.distance import vincenty
  
  df
  
  
       city_name  state_name  county_name
  0    WASHINGTON  DC  DIST OF COLUMBIA
  1    WASHINGTON  DC  DIST OF COLUMBIA
  2    WASHINGTON  DC  DIST OF COLUMBIA
  3    WASHINGTON  DC  DIST OF COLUMBIA
  4    WASHINGTON  DC  DIST OF COLUMBIA
  5    WASHINGTON  DC  DIST OF COLUMBIA
  6    WASHINGTON  DC  DIST OF COLUMBIA
  7    WASHINGTON  DC  DIST OF COLUMBIA
  8    WASHINGTON  DC  DIST OF COLUMBIA
  9    WASHINGTON  DC  DIST OF COLUMBIA
  </code></pre>
  
  <p>I want to get the latitude and longitude coordinates for any one of the columns in the data frame below.  The documentation (<a href="http://geopy.readthedocs.org/en/latest/#data">http://geopy.readthedocs.org/en/latest/#data</a>) is pretty straightforward when working with the documentation for individual locations. </p>
  
  <pre><code>&gt;&gt;&gt; from geopy.geocoders import Nominatim
  &gt;&gt;&gt; geolocator = Nominatim()
  &gt;&gt;&gt; location = geolocator.geocode("175 5th Avenue NYC")
  &gt;&gt;&gt; print(location.address)
  Flatiron Building, 175, 5th Avenue, Flatiron, New York, NYC, New York,     ...
  &gt;&gt;&gt; print((location.latitude, location.longitude))
  (40.7410861, -73.9896297241625)
  &gt;&gt;&gt; print(location.raw)
  {'place_id': '9167009604', 'type': 'attraction', ...}
  </code></pre>
  
  <p>However I want to apply the function to each row in the df and make a new column.  I've tried the following </p>
  
  <pre><code>df['city_coord'] = geolocator.geocode(lambda row: 'state_name' (row))
  </code></pre>
  
  <p>but I think I'm missing something in my code because I get the following:</p>
  
  <pre><code>    city_name   state_name  county_name coordinates
  0    WASHINGTON  DC  DIST OF COLUMBIA    None
  1    WASHINGTON  DC  DIST OF COLUMBIA    None
  2    WASHINGTON  DC  DIST OF COLUMBIA    None
  3    WASHINGTON  DC  DIST OF COLUMBIA    None
  4    WASHINGTON  DC  DIST OF COLUMBIA    None
  5    WASHINGTON  DC  DIST OF COLUMBIA    None
  6    WASHINGTON  DC  DIST OF COLUMBIA    None
  7    WASHINGTON  DC  DIST OF COLUMBIA    None
  8    WASHINGTON  DC  DIST OF COLUMBIA    None
  9    WASHINGTON  DC  DIST OF COLUMBIA    None
  </code></pre>
  
  <p>I would like something like this hopefully using the Lambda function:</p>
  
  <pre><code>     city_name  state_name  county_name  city_coord
  0    WASHINGTON  DC  DIST OF COLUMBIA    38.8949549, -77.0366456 
  1    WASHINGTON  DC  DIST OF COLUMBIA    38.8949549, -77.0366456 
  2    WASHINGTON  DC  DIST OF COLUMBIA    38.8949549, -77.0366456 
  3    WASHINGTON  DC  DIST OF COLUMBIA    38.8949549, -77.0366456 
  4    WASHINGTON  DC  DIST OF COLUMBIA    38.8949549, -77.0366456 
  5    WASHINGTON  DC  DIST OF COLUMBIA    38.8949549, -77.0366456 
  6    WASHINGTON  DC  DIST OF COLUMBIA    38.8949549, -77.0366456 
  7    WASHINGTON  DC  DIST OF COLUMBIA    38.8949549, -77.0366456 
  8    WASHINGTON  DC  DIST OF COLUMBIA    38.8949549, -77.0366456 
  9    WASHINGTON  DC  DIST OF COLUMBIA    38.8949549, -77.0366456
  10   GLYNCO      GA  GLYNN               31.2224512, -81.5101023
  </code></pre>
  
  <p>I appreciate any help.  After I get the coordinates I'd like to map them.  Any recommended resources for mapping coordinates is greatly appreciated too. thanks</p>