[R] For is.numeric condition in user input

[Bansal, Vikas]

Thanks for your reply.But I have never seen ia.na in R.Can you please tell me how to use this?
So you are saying rather than is.numeric,I have to test user input by ia.na?


Thanking you,
Warm Regards
Vikas Bansal
Msc Bioinformatics
Kings College London
________________________________________
From: jim holtman [jholtman at gmail.com]
Sent: Monday, July 25, 2011 12:58 PM
To: Bansal, Vikas
Cc: Smart Guy; Ista Zahn; r-help at r-project.org
Subject: Re: [R] For is.numeric condition in user input

If you run a simple test (that is what is nice about R being
interpreted), you will see that 'as.numeric' is TRUE; what you want to
test for is 'ia.na':

> a
[1] "12as"
> as.numeric(a)
[1] NA
Warning message:
NAs introduced by coercion
> is.numeric(as.numeric(a))
[1] TRUE
Warning message:
NAs introduced by coercion



On Mon, Jul 25, 2011 at 7:49 AM, Bansal, Vikas <vikas.bansal at kcl.ac.uk> wrote:
> Thanks for your reply.I know readline will give me a character.But if I will do something like this-
>
>
>> readnumber<- function()
>>  {
>> for(j in 1:10){
>>  value=readline("enter the threshold for number of reads: ")
>> value=as.numeric(value)
>>  if(is.numeric(value)==T)
>> {return(value)
>> break}
>> else
>> print("wrong number Please enter numerical value ")}
>>
>>  }
>
> if i will change value as numeric and if now user will input a character like a or b rather than a number like 4 or 5 or 6,then my code is not showing message-
> wrong number Please enter numerical value
>
> That is why I am confused now-I have tried with- value=as.numeric(value)
> and without this also.But did not find any solution.
>
>
> Thanking you,
> Warm Regards
> Vikas Bansal
> Msc Bioinformatics
> Kings College London
> ________________________________________
> From: Smart Guy [smartguy3k at gmail.com]
> Sent: Monday, July 25, 2011 6:39 AM
> To: Ista Zahn
> Cc: Bansal, Vikas; r-help at r-project.org
> Subject: Re: [R] For is.numeric condition in user input
>
> Yes, thats right, readline will give you character and now you need to convert it to numeric to make it work.
>
> Thanks
> SmartG
>
> On 25 July 2011 08:51, Ista Zahn <izahn at psych.rochester.edu<mailto:izahn at psych.rochester.edu>> wrote:
> readline always returns a character. See ?readline for details.
>
> Best,
> Ista
>
> On Sun, Jul 24, 2011 at 10:59 PM, Bansal, Vikas <vikas.bansal at kcl.ac.uk<mailto:vikas.bansal at kcl.ac.uk>> wrote:
>> Dear all,
>>
>> I am using the following function so that user can input a numerical value.
>>
>> readnumber<- function()
>>  {
>> for(j in 1:10){
>>  value=readline("enter the threshold for number of reads: ")
>>  if(is.numeric(value)==T)
>> {return(value)
>> break}
>> else
>> print("wrong number Please enter numerical value ")}
>>
>>  }
>>
>> But if by chance user tries to put character it will show the message-
>>  wrong number Please enter numerical value
>>
>> now when I am calling this function and entering numerical value,then also it is showing the message-wrong number Please enter numerical value
>>
>> Can you please tell me what mistake I am doing?
>>
>>
>>
>>
>>
>>
>>
>> Thanking you,
>> Warm Regards
>> Vikas Bansal
>> Msc Bioinformatics
>> Kings College London
>> ______________________________________________
>> R-help at r-project.org<mailto: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.
>>
>
>
>
> --
> Ista Zahn
> Graduate student
> University of Rochester
> Department of Clinical and Social Psychology
> http://yourpsyche.org
>
> ______________________________________________
> R-help at r-project.org<mailto: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.
>
>
>
> --
> SmartG
>
> ______________________________________________
> 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.
>



--
Jim Holtman
Data Munger Guru

What is the problem that you are trying to solve?