Celsius to Fahrenheit conversion in CSV file

I want to take a CSV file with Temperatures in celsius and convert it to fahrenheit.

Current attempt:

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)

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:

can't multiply sequence by non-int of type 'float'

I've tried to convert values to float but I've had no luck.

Edit: The CSV file that I am using is multi column. It has more than simply air temp in it.

Also here is full traceback

`---------------------------------------------------------------------------
TypeError                                 Traceback (most recent call last)
<ipython-input-4-a63269740c5c> in <module>()
----> 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
-> 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):
-> 4138                     results[i] = func(v)
   4139                     keys.append(v.name)
   4140             except Exception as e:

<ipython-input-3-895f5da25595> in f(x)
      1 def f(x):
----> 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 
--> 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)
--> 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')

I've not used Pandas before but reviewing the documentation, this looks like it should work:

df['Air Temperature'] = df['Air Temperature'].apply(f)

'Air Temperature' is a series in the DataFrame, and the series object also has an apply method.