Can anyone explain this error [AttributeError: 'DataFrame' object has no attribute 'to_numeric']
<p>I'm tryting to change the salaries to the intergers so I can then do some analysis and make a chart of their price per pitch. When I try to do this it says that the dataframe doesnt have the attribute to_numeric. I got the code of the API DOCs so I was wondering what is happening. Is it a list of DataFrames or something. Should I change the number signs out of it?</p>

<pre><code>import pandas as pd
import pandas_datareader.data as web

players = pd.read_html('http://www.usatoday.com/sports/mlb/salaries/2013/player/p/')


df1 = pd.DataFrame(players[0])
df1.drop(df1.columns[[0,3,4, 5, 6]], axis=1, inplace=True)
df1.columns = ['Player', 'Team', 'Avg_Annual']
#print (df1.head(10))

p2 = pd.read_html('http://www.sportingcharts.com/mlb/stats/pitching-pitch-count-leaders/2013/')


df2 = pd.DataFrame(p2[0])

df2.drop(df2.columns[[0,2, 3]], axis=1, inplace=True)



#print (df2.head(10))

df1.set_index ('Player')
df2.set_index('Player')




df3 = pd.merge(df1, df2, on='Player')

df3.set_index('Player', inplace=True)
df3.columns = ['Team', 'Avg_Annual', 'Pitch_Count']
print (df3.head())

df3.to_numeric(Avg_Annual)
values = (df3.Avg_Annual) - (df3.Pitch_Count)

print (values.head())
</code></pre>

<p>Which gives error:</p>

<blockquote>
  <p>Traceback (most recent call last): File "/home/mdz5032/PMLB.py", line
  38, in  df3.to_numeric(Avg_Annual) File
  "/usr/local/lib/python3.4/dist-packages/pandas/core/generic.py", line
  2672, in getattr return object.<strong>getattribute</strong>(self, name)
  AttributeError: 'DataFrame' object has no attribute 'to_numeric'</p>
</blockquote>