[R] Error in if-command

[arun]

HI,

Your second function works:
fun2<-function(y){
 if(y==2){
 print("yes")}
 else {print("no")}}
 fun2(3)
#[1] "no"
 fun2(4)
#[1] "no"
 fun2(2)
#[1] "yes"


But, in the first case, it is a vector.
So, you can use:
fun3<-function(y){
 numbers1<-c(4,5,9,11,17)
 if(y %in% numbers1){
 print("yes")}
 else {print("no")}
 }
 fun3(8)
#[1] "no"
 fun3(9)
#[1] "yes"
 fun3(10)
#[1] "no"
 fun3(11)
#[1] "yes"
A.K.





----- Original Message -----
From: Dominic Roye <dominic.roye at gmail.com>
To: r-help at r-project.org
Cc: 
Sent: Sunday, August 12, 2012 6:12 AM
Subject: [R] Error in if-command

Hello everybody,

I don't understand what I'm doing wrong. But it isn't possible that each
element of the if-condition is tested for each vector element?

y <- c(1:20)
> y
[1]  1  2  3  4  5  6  7  8  9 10 11 12 13 14 15 16 17 18 19 20

> if (y == c(4,5,9,11,17)) { print("yes")  } else { print("no")}
[1] "no"
warning:
In if (y == c(4, 5, 9, 11, 17)) { :
  Condition has length > 1 and only the first element is used
>


#It also doesn't work with this condition ==2

if (y == 2) { print("yes")  } else { print("no")}
[1] "no"
warning:
In if (y == 2) { :
Condition has length> 1 and only the first element is used



I guess it's a trivial problem. I hope someone can help me.

Thank you!

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