(take 100 (iterate rand-int 300))
evaluates differently, of course, each time... but usually with a ton of zeros. The result always leads with a 300. For example:
(300 93 59 58 25 14 9 4 2 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0)
I would have expected 100 random integers between 0 and 300.
What am I not understanding?
See docs for iterate:
Returns a lazy sequence of x, (f x), (f (f x)) etc. f must be free of side-effects
So, that's the reason your sequence is always starting with 300.
And why there are so many zeros? When you use iterate like this, rand-int takes the previous result and uses it as a new upper limit (exclusive) for a random number. So, your results can look like this:
300
=> 300
(rand-int *1)
=> 174
(rand-int *1)
=> 124
(rand-int *1)
=> 29
(rand-int *1)
=> 17
(rand-int *1)
=> 16
(rand-int *1)
=> 7
...
You can check yourself that this sequence leads to zero.
If you really want to get 100 random integers between 0 and 300, use repeatedly instead:
(repeatedly 100 #(rand-int 300))