Im new to python and was wondering how i would go about looping through all values in my dates column and counting how many different dates there are within it in total.

I know it is possible to do this by using the .nunique() function but i am looking for how to do this using a For loop.

my data frame is simply a table with 1 column of different dates. within my actual data i have over 500 different rows so i have cut it down to just 10 for this. For this example i expect the result to be 4.

```
date_tbl

Index    Date
0        07/08/2015
1        07/08/2015
2        07/08/2015
3        08/08/2015
4        08/08/2015
5        08/08/2015
6        08/08/2015
7        09/08/2015
8        09/08/2015
9        10/08/2015

```

Any help would be appreciated, thanks.