return floats instead of ndarray in pandas - python -

>>> df=pd.dataframe({'c1':[1,1,1,1,2,2,2,2],'c2':['a','b','a','b','a','a','b','b'],'c3':['w','w','x','x','w','x','w','x'],'c4':[90,28,31,10,21,55,49,23]})  >>> groups = df.groupby(['c1','c3'])  >>> groups.apply(lambda x: x[x['c2']=='b'].c4.values / x[x['c2']=='a'].c4.values)  c1   c2    1    w    [0.31111]      x    [0.32258] 2    w    [2.33333]      x    [0.41818] 

is there way make operation above return float values instead of ndarray?

c1   c2    1    w    0.31111      x    0.32258 2    w    2.33333      x    0.41818 

i think can convert output series:

df = groups.apply(lambda x: pd.series(x[x['c2']=='b'].c4 / x[x['c2']=='a'].c4.values))            .reset_index(level=2, drop=true) print (df) c1  c3 1   w     0.311111     x     0.322581 2   w     2.333333     x     0.418182 name: c4, dtype: float64