#example bitwise operator vs lazy operator 

 a= c(1,1)
 b= c(1,3)
 d= c(2,1)
 
 a==1 & b==1 #it evaluates all positions
 
 a==1 && b==1 #it evaluates only the first position
 a==1 && d==1 #it evaluates only the first position
 
 a==1  || z==1 #it evaluates only what is necessary

 a==1 | z==1 #it evaluates all
 

myfunif=function(){ 
  if (a==1 && b==1) {
    cat("True\n")
  }
  else{
   cat("False\n")
  }
}
myfunif()


myfunif1=function(){ 
  if (a==1 & b==1) {
    cat("True\n")
  }
  else{
    cat("False\n")
  }
}
myfunif1()