[R] how to do a IF ELSE in a matrix format

[Hey Sky]

Hey, Rers

I am new to R and this question may has been asked many times or a very old 
one. I have checked 

the archive but found nothing (maybe I used the wrong key words). any advise is 
appreciated

the question is:

I try to replace a col vector with some other values, see

edu<-matrix(0,1000,2)

edu1<-runif(1000,0,1)
edu[,1]<-edu1

the colum  vector edu[,1]  would have value between 0 and 1. if I want to 
replace the value of edu[,2] 

to 1 if edu[,1] less than 0.5, how to do it in the form of matrix but not under 
a loop structure?

I have tried: 

if (edu[,1]>=0.5) edu[,2]=1

there is only the first 0.5 have been done but not all the others. thanks for 
any kind answer.

Nan
from Montreal