[R] Error in if loop

Mark Wardle mark at wardle.org
Sun Oct 21 17:08:40 CEST 2007

On 21/10/2007, stat stat <stat700004 at yahoo.co.in> wrote:
> I have created a if loop as follows:
> name = "e"
> if (name == "v")
>   {
>    u = 0
> }
> else u = 1
> however i am getting error : Error: unexpected 'else' in "else"

There are 3 issues here:

1. Do you appreciate the difference between ifelse and if ? What are
you actually trying to do - in this context, ifelse would usually be
more sensible but as you've not said what you want to do, it is
difficult to guess.
2. I don't get the same error as you. Which version of R are you using?

> if (name=="v")
+ {
+ u=0
+ }
> else u=1
Error: syntax error

This error message makes it clear that there is a syntax problem. In
fact, look at the lefthand column of characters and you should see
what the problem is....

3. R is interpreting your code as two separate expressions because you
are using an interactive shell. Try this instead:

if (name=='v') {
} else {

Hope this helps.

Best wishes,


Dr. Mark Wardle
Specialist registrar, Neurology
Cardiff, UK

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