Hello!
I'd like to get some advice.
I have the following forms of data.

I'd like to change all the "thrifty" values to zero for a certain period of time.
In the data below, for example, I would like to change all the values of thrift from 01apr2015 to 02apr2015.
If it goes as I intended, then "thrifty_nb" should be created.
(The thrift value is only 0 or 1)

Thanks!

Code:
* Example generated by -dataex-. To install: ssc install dataex
clear
input float(id date thrifty thrifty_nb)
1 20148 0 0
1 20149 0 0
1 20150 1 1
1 20179 1 0
1 20180 0 0
2 20149 0 0
2 20150 0 0
2 20151 1 1
2 20179 1 0
2 20180 1 0
2 20181 1 1
end
format %td date