[R] Can anyone help why the errors are coming and rectify it?

[R. Michael Weylandt]

And now it is easy to see why we should all the one true brace style ;-)

Michael

On Mon, Sep 17, 2012 at 12:29 PM, Ted Harding <Ted.Harding at wlandres.net> wrote:
> On 17-Sep-2012 09:47:41 Sri krishna Devarayalu Balanagu wrote:
>> Hi Everyone,
>> Can anyone help why the errors are coming and rectify it?
>>
>> invalid.ids <- c(1,3,5)
>> if (length(invalid.ids)==0)   {
>>
>> cat("No Errors found")
>>                                                        }
>> else                                              {
>>
>> cat(paste(invalid.ids), sep="\n")
>>                                                       }
>>
>> Error: unexpected 'else' in "else"
>> Error: unexpected '}' in "        }"
>>
>> Thank you in advance
>>
>> Warm Regards
>> Rayalu
>
> Reformatting your code (for readability) but preserving your
> line breaks:
>
>   invalid.ids <- c(1,3,5)
>   if (length(invalid.ids)==0) {
>     cat("No Errors found")
>   }
>   else {
>     cat(paste(invalid.ids), sep="\n")
>   } }
>
>   Error: unexpected 'else' in "else"
>   Error: unexpected '}' in "        }"
>
> First:
>
> The first four lines are a completed command, given the way
> that R parses input. After encountering the end-of-line at
> the fourth line, R considers that it has seen a complete command
> and therefore executes it.
>
>  invalid.ids <- c(1,3,5)
>   if (length(invalid.ids)==0) {
>     cat("No Errors found")
>   }
>
> Therefore the "else {" on the next line is not interpreted as
> if it were part of the preceding "if()" statement, since that
> has been considered complete and has been executed. So that
> "else" is an "else" with no matching "if". Henc the the first
> error message.
>
> Second: if you count the opening "{" and closing "}", you will
> see that there is one "}" too many, at the end, hence the second
> error message.
>
> The way to avoid the first error message is to put the "else"
> on the same line as the close of the "if" statement. Then R will
> recognise that it has an incomplete commend, and continue to parse
> further input until it has built up a complete command. So you
> should write:
>
>   invalid.ids <- c(1,3,5)
>   if (length(invalid.ids)==0) {
>     cat("No Errors found")
>   } else {
>     cat(paste(invalid.ids), sep="\n")
>   }
>
> (Note that the extra "}" has been omitted too).
>
> Hoping this helps,
> Ted.
>
>
> -------------------------------------------------
> E-Mail: (Ted Harding) <Ted.Harding at wlandres.net>
> Date: 17-Sep-2012  Time: 12:29:46
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