title: Celsius to Fahrenheit conversion in CSV file
body: <p>I want to take a CSV file with Temperatures in celsius and convert it to fahrenheit. </p>
  
  <p>Current attempt:</p>
  
  <pre><code>import pandas as pd
  df = pd.read_csv('/temperature_data.csv', )
  
  def f(x):
      x = x * 1.8 + 32
      return float(x)
  
  df['AirTemperature'] = df.apply(f, axis=1)
  </code></pre>
  
  <p>I am able to successfully do this if I simply input an integer into the function, but I keep getting this error message when I try to use the csv file:</p>
  
  <pre><code>can't multiply sequence by non-int of type 'float'
  </code></pre>
  
  <p>I've tried to convert values to float but I've had no luck.</p>
  
  <p>Edit: 
  The CSV file that I am using is multi column. It has more than simply air temp in it.</p>
  
  <p>Also here is full traceback</p>
  
  <pre><code>`---------------------------------------------------------------------------
  TypeError                                 Traceback (most recent call last)
  &lt;ipython-input-4-a63269740c5c&gt; in &lt;module&gt;()
  ----&gt; 1 df['AirTemperature'] = df.apply(f, axis=1)
  
  /Users/pvayn/anaconda/lib/python2.7/site-packages/pandas/core/frame.pyc in apply(self, func, axis, broadcast, raw, reduce, args, **kwds)
     4040                     if reduce is None:
     4041                         reduce = True
  -&gt; 4042                     return self._apply_standard(f, axis, reduce=reduce)
     4043             else:
     4044                 return self._apply_broadcast(f, axis)
  
  /Users/pvayn/anaconda/lib/python2.7/site-packages/pandas/core/frame.pyc in _apply_standard(self, func, axis, ignore_failures, reduce)
     4136             try:
     4137                 for i, v in enumerate(series_gen):
  -&gt; 4138                     results[i] = func(v)
     4139                     keys.append(v.name)
     4140             except Exception as e:
  
  &lt;ipython-input-3-895f5da25595&gt; in f(x)
        1 def f(x):
  ----&gt; 2     x = x*1.8 + 32
        3     return float(x)
  
  /Users/pvayn/anaconda/lib/python2.7/site-packages/pandas/core/ops.pyc in wrapper(left, right, name, na_op)
      647                 lvalues = lvalues.values
      648 
  --&gt; 649             return left._constructor(wrap_results(na_op(lvalues, rvalues)),
      650                                      index=left.index, name=left.name,
      651                                      dtype=dtype)
  
  /Users/pvayn/anaconda/lib/python2.7/site-packages/pandas/core/ops.pyc in na_op(x, y)
      588                 result = np.empty(len(x), dtype=x.dtype)
      589                 mask = notnull(x)
  --&gt; 590                 result[mask] = op(x[mask], y)
      591             else:
      592                 raise TypeError("{typ} cannot perform the operation "
  
  TypeError: ("can't multiply sequence by non-int of type 'float'", u'occurred at index 0')
  </code></pre>