Divide two pandas Series

Question

trying to divide 2 series but im getting a behavior i dont understand

a = 14    0.27
    15    0.11
    16    0.00
    dtype: float64

a.index returns

Int64Index([14, 15, 16], dtype='int64')

and

b = 14    0.150286
    15    0.108026
    16    0.000000
    dtype: float64

b.index returns

Index([u'14', u'15', u'16'], dtype='object')

When i do

a.divide(b) or a/b

i get the same result

14   NaN
15   NaN
16   NaN
14   NaN
15   NaN
16   NaN

this should be pretty simple but i dont understand why is returning the series instead of returning the expected

   14   1.7965
   15   1.0182
   16   NaN

Answer 1

I think there are different dtypes of indexes, so need same type - e.g. cast object (obviously str) to int:

a = pd.Series([0.27, 0.11, 0], index=['14','15','16'])
b = pd.Series([0.150286, 0.108026, 0], index=[14,15,16])
print (a)
14    0.27
15    0.11
16    0.00
dtype: float64

print (b)
14    0.150286
15    0.108026
16    0.000000
dtype: float64

print (a.index.dtype)
object
print (b.index.dtype)
int64

#cast to int
a.index = a.index.astype(int)
print (a.div(b))
14    1.796575
15    1.018273
16         NaN
dtype: float64

Answer 2

Switching to numpy arrays and getting back to a pandas series afterwards can also work:

a = pd.Series([0.27, 0.11, 0], index=['14','15','16'])
b = pd.Series([0.150286, 0.108026, 0], index=[14,15,16])

# the index to keep 
my_index = a.index()

c = a.values / b.values
c = pd.Series(c, index=my_index)