Dear all,

I am entirely new to stata, so in case I am leaving out any information that might be required to help me, I am already apologising in advance.
I want to calculate the daily stock returns for multiple companies based on the following data:

Date ISIN 1 ISIN 2 ISIN 3 ISIN 4
4/28/2021 3.23 15350 .2765 1.5935
4/27/2021 3.23 15350 .2765 1.5935
4/26/2021 3.3 15500 .2815 1.59
4/23/2021 3.28 15170 .28 1.593
4/22/2021 3.3 14865 .265 1.59
4/21/2021 3.33 15105 .274 1.56
4/20/2021 3.31 14895 .282 1.562
4/19/2021 3.33 15220 .287 1.5785
4/16/2021 3.33 15300 .2865 1.56


Just an abstract of course. The numbers you see are the daily stock prices. How can I replace these numbers with the daily stock return (price t+1 - price t) / price t for each variable.

Any help is highly appreciated.