Question

Here’s what I have…

Select[roll, # <= 3 &]

Now, the list that follows may have one 3 or two three’s. I want it to stop at the first three from left to right.

Mathematician trying to code.

Answer 1

Note: I removed my original posting, which was basically like that of belisarius. Here’s another try…

If you are sure that the number 3 is a member of roll then this should work:

TakeWhile[roll, # != 3 &]~Append~3

This is equivalent to:

Take[roll, LengthWhile[roll, # != 3 &] +1]

If you cannot make this assumption, just test first with MemberQ

EDIT: Credit goes to TomD for suggesting the +1 in the second solution, which eliminates the need to use Append.