# What do brackets around a levelspec option do?

The following code returns the first three integer elements of Sqrt[Range[100]]:

Cases[Sqrt[Range[100]], _Integer, 2, 3]
{1, 2, 3}


The following code looks like the preceding code but returns a different result:

Cases[Sqrt[Range[100]], _Integer, {2}, 3]
{2, 3, 5}


As we can see in the following picture, the argument {2} is not documented (it has no braces in the documentation):

What does the second code with {2} instead of 2 mean?

• see documentation carefully it is there. – Rorschach Aug 3 '13 at 6:25
• This is buried in the documentation. I had this same question about Level[] and wouldn't have known to look in the Cases[] documentation. I only found this page with community help. – Jerry Guern Mar 10 '17 at 1:59

• I agree than not all need to be closed, but in this case, the answer is almost on top. I do not demand anything, I have also not reason to doubt in your intentions, I just wanted to ask to avoid working against community by voting to close. By "keep repository transparent." I meant, we can rewrite documentation here be such database would be not handy. It is also due to search engine but it is a long story... :) ("Levels: how do...", shoud be easily found by typing "levels" etc. but it isn't due to ":" in the title, check title:levels: is:question and title:levels is:question) – Kuba Aug 5 '13 at 8:24