HELP- DATA FRAME INTO TIME SERIES- BASIC

[bntayfur]

Ok, so i have a data frame and i want to change it to time series.

Output:
   Month  Sales  Inflation
0  1-Jan  266.0          1
1  2-Jan  145.9          3
2  3-Jan  183.1          5
3  4-Jan  119.3          5
4  5-Jan  180.3          4

For some reason,below code did not work.(also if anyone can explain what it means it would help a lot i just found the code from tutorial, didn't really get it)

shampoo= pd.read_csv('shampoo_with_exog.csv', index_col=[0], parse_dates= True,squeeze=True)

Since it didn't work, i am wanted to do it manually. What i want to do is only to keep the Jan,Feb,... and strip up until including '-' for all in Months column

def month_converter(month):
    months = ['Jan', 'Feb', 'Mar', 'Apr', 'May', 'Jun', 'Jul', 'Aug', 'Sep', 'Oct', 'Nov', 'Dec']
    return months.index(month) + 1

### this is the code for the striping part which i don't know how to do!!! Then,

for i in shampoo.Month :
    month_converter(i)
    

---

shampoo_index = shampoo['Month'].str.index('-')

shampoo.Month = shampoo['Month'].str[(shampoo_index+1):]

for i in shampoo.Month :
    month_converter(i)

Why doesn't this work?

---

SOMEONE PLEASE HELP!

Error:
Can only use .str accessor with string values, which use np.object_ dtype in pandas