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

[Jessica Streicher]

Now i know why using else never worked for me - really, i'd consider this more of a bug than a feature of the language ;)

On 17.09.2012, at 14:35, R. Michael Weylandt wrote:

> 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
>> This message was sent by XFMail
>> 
>> ______________________________________________
>> R-help at r-project.org mailing list
>> https://stat.ethz.ch/mailman/listinfo/r-help
>> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
>> and provide commented, minimal, self-contained, reproducible code.
> 
> ______________________________________________
> R-help at r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.