Data type conversion error: ValueError: Cannot convert non-finite values (NA or inf) to integer

I’ve the following dataframe

df1 = df[['tripduration','starttime','stoptime','start station name','end station name','bikeid','usertype','birth year','gender']]
print(df1.head(2))

which prints the following

tripduration            starttime             stoptime start station name  
0           364  2017-09-01 00:02:01  2017-09-01 00:08:05     Exchange Place   
1           357  2017-09-01 00:08:12  2017-09-01 00:14:09          Warren St   

   end station name  bikeid    usertype  birth year  gender  
0  Marin Light Rail   29670  Subscriber      1989.0       1  
1      Newport Pkwy   26163  Subscriber      1980.0       1

I am using the following code to convert “birth year” column type from float to int.

df1[['birth year']] = df1[['birth year']].astype(int)
print df1.head(2)

But I get the following error. How to fix this?

ValueErrorTraceback (most recent call last)
<ipython-input-25-0fe766e4d4a7> in <module>()
----> 1 df1[['birth year']] = df1[['birth year']].astype(int)
      2 print df1.head(2)
      3 __zeppelin__._displayhook()

/usr/miniconda2/lib/python2.7/site-packages/pandas/util/_decorators.pyc in wrapper(*args, **kwargs)
    116                 else:
    117                     kwargs[new_arg_name] = new_arg_value
--> 118             return func(*args, **kwargs)
    119         return wrapper
    120     return _deprecate_kwarg

/usr/miniconda2/lib/python2.7/site-packages/pandas/core/generic.pyc in astype(self, dtype, copy, errors, **kwargs)
   4002         # else, only a single dtype is given
   4003         new_data = self._data.astype(dtype=dtype, copy=copy, errors=errors,
-> 4004                                      **kwargs)
   4005         return self._constructor(new_data).__finalize__(self)
   4006 

/usr/miniconda2/lib/python2.7/site-packages/pandas/core/internals.pyc in astype(self, dtype, **kwargs)
   3460 
   3461     def astype(self, dtype, **kwargs):
-> 3462         return self.apply('astype', dtype=dtype, **kwargs)
   3463 
   3464     def convert(self, **kwargs):

/usr/miniconda2/lib/python2.7/site-packages/pandas/core/internals.pyc in apply(self, f, axes, filter, do_integrity_check, consolidate, **kwargs)
   3327 
   3328             kwargs['mgr'] = self
-> 3329             applied = getattr(b, f)(**kwargs)
   3330             result_blocks = _extend_blocks(applied, result_blocks)
   3331 

/usr/miniconda2/lib/python2.7/site-packages/pandas/core/internals.pyc in astype(self, dtype, copy, errors, values, **kwargs)
    542     def astype(self, dtype, copy=False, errors='raise', values=None, **kwargs):
    543         return self._astype(dtype, copy=copy, errors=errors, values=values,
--> 544                             **kwargs)
    545 
    546     def _astype(self, dtype, copy=False, errors='raise', values=None,

/usr/miniconda2/lib/python2.7/site-packages/pandas/core/internals.pyc in _astype(self, dtype, copy, errors, values, klass, mgr, **kwargs)
    623 
    624                 # _astype_nansafe works fine with 1-d only
--> 625                 values = astype_nansafe(values.ravel(), dtype, copy=True)
    626                 values = values.reshape(self.shape)
    627 

/usr/miniconda2/lib/python2.7/site-packages/pandas/core/dtypes/cast.pyc in astype_nansafe(arr, dtype, copy)
    685 
    686         if not np.isfinite(arr).all():
--> 687             raise ValueError('Cannot convert non-finite values (NA or inf) to '
    688                              'integer')
    689 

ValueError: Cannot convert non-finite values (NA or inf) to integer