[R] What does 'collapse' mean in apply()?

[Peng Yu]

Hi,

I can't find 'collapse' in the help of apply. Can somebody let me know
where its document is? What is 'collapse' for?

> x=matrix(1:6,nr=2)
> apply(x,1,paste,collapse=',')
[1] "1,3,5" "2,4,6"
>

Regards,
Peng