r - Filling an empty vector -


here's super newbie question. i'm working through art of r programming , came across simple code: 

z <- null  (i in 1:10) if (i %% 2 == 0) z <- c(z,i) z

the output c(2,4,6,8,10).

what don't understand why need c(z,i) populate vector z. why wouldn't c(i) work. when that, skips straight last iteration , fills vector z last associated value. there form of rule governs populating vectors? try might, didn't find clear answer anywhere, bunch of samples that, while made sense, didn't me solve above.


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