title: How to replace dataframe columns country name with continent?
body: <p>I have Dataframe like this.</p>
  
  <pre><code>problem.head(30)
  Out[25]: 
       Country
  0     Sweden
  1     Africa
  2     Africa
  3     Africa
  4     Africa
  5    Germany
  6    Germany
  7    Germany
  8    Germany
  9         UK
  10   Germany
  11   Germany
  12   Germany
  13   Germany
  14    Sweden
  15    Sweden
  16    Africa
  17    Africa
  18    Africa
  19    Africa
  20    Africa
  21    Africa
  22    Africa
  23    Africa
  24    Africa
  25    Africa
  26  Pakistan
  27  Pakistan
  28        ZA
  29        ZA
  </code></pre>
  
  <p>Now i want to replace the country name with the continent name. So the country name will be replace with its continent name.</p>
  
  <p>What i did is, i have created all the Continent array(which is there in my data frame, i have 56 country), </p>
  
  <pre><code>asia = ['Afghanistan', 'Bahrain', 'United Arab Emirates','Saudi Arabia', 'Kuwait', 'Qatar', 'Oman',
      'Sultanate of Oman','Lebanon', 'Iraq', 'Yemen', 'Pakistan', 'Lebanon', 'Philippines', 'Jordan']
  europe = ['Germany','Spain', 'France', 'Italy', 'Netherlands', 'Norway', 'Sweden','Czech Republic', 'Finland',
        'Denmark', 'Czech Republic', 'Switzerland', 'UK', 'UK&amp;I', 'Poland', 'Greece','Austria',
        'Bulgaria', 'Hungary', 'Luxembourg', 'Romania' , 'Slovakia', 'Estonia', 'Slovenia','Portugal',
        'Croatia', 'Lithuania', 'Latvia','Serbia', 'Estonia', 'ME', 'Iceland' ]
  africa = ['Morocco', 'Tunisia', 'Africa', 'ZA', 'Kenya']
  other = ['USA', 'Australia', 'Reunion', 'Faroe Islands']
  </code></pre>
  
  <p>Now trying to replace using</p>
  
  <pre><code>dataframe['Continent'] = dataframe['Country'].replace(asia, 'Asia', regex=True)
  </code></pre>
  
  <p>where asia is my list name and Asia is text to be replace. But is not working
  it only work for</p>
  
  <pre><code>dataframe['Continent'] = dataframe['Country'].replace(np.nan, 'Asia', regex=True)
  </code></pre>
  
  <p>So, help will be appreciated </p>