%RANDOM% environment variable is giving a single number

Question

I’m having trouble with the %RANDOM% environment variable in the following command:

FOR /l %%A in (0,1,30) do set /a results=1600 + %RANDOM% %% (1900 - 1600 + 1) && echo %%A--!results!

I expect this output:

0--1656
1--1743
2--1629
3--1887
…

But I’m getting this:

0--1656
1--1656
2--1656
3--1656
…

The %RANDOM% variable is supposed to return a random number, but it’s giving the same number. What’s the problem and how can I fix it?

@WernerHenze, actually it’s not; it’s closer to [this question](http://superuser.com/questions/78496/). — Synetech, Nov 19 '13 at 17:24
@Synetech OK, but at least the answers in the question I linked give the answer to the question here :). — Werner Henze, Nov 19 '13 at 17:28

score 1 · Accepted Answer · answered Nov 19 '13 at 17:22

1

You need to use delayed expansion for the RANDOM variable as well:

FOR /l %%A in (0,1,30) do set /a results=1600 + !RANDOM! %% (1900 - 1600 + 1) && echo %%A--!results!

Screenshot of command-prompt with expected results from script

answered Nov 19 '13 at 17:22

Synetech

Thanks... By using delayed expansion, it worked the way I wanted. – hbelouf Nov 19 '13 at 17:31
You were already using delayed expansion on the `results` variable, you just forgot to use on the `random` variable. You need to use `!` in place of `%` for *all* variables in a `for` loop. `;-)` – Synetech Nov 19 '13 at 17:41

1 Answers1