[R] Error non-numeric argument to binary operator

[Uwe Ligges]

On 13.07.2011 17:46, Bansal, Vikas wrote:
> Dear all,
>
> I have a data frame df and i am using a code shown below.
>
> df[, "total"]<- rowSums(df[, 3:6])          MAKING A NEW COLUMN total in df BY ROWSUMS
>
>   defineSamples<- function()
>   {
>   readline("enter the number of INDIVIDUALS IN POOL: ")
>   }
> df$ind=definesamples()      CALLING THE FUNCTION AND STORING THE INPUT FROM USER IN NEW COLUMN OF df


This won't work, because

1. defineSamples != definesamples

2. readline returns a character but you expect a numeric value - which 
is why you get the error message. Just coerce to numeric and implement a 
careful check if the entered value can be coerced successfully.

Uwe Ligges




> df[, 3:6]<- apply(df[, 3:6], 2, function(x) x / df[, "total"] * df[, "ind"] * 2)        APPLYING A MATHEMATICAL FORMULA
>
> I am taking an input from user which is stored in ind column of df.and then i am applying a formula showed in last line of code.
> But it shows this error-
>
> Error in x/df[, "total"] * df[, "ind"]  :
>    non-numeric argument to binary operator
>
> but if i am not taking input from user and using straight way this-
> df$ind=9
> then it is working.
>
> But i want to enter the value of ind from user.Can you please tell me how can i remove this error.

> Thanking you,
> Warm Regards
> Vikas Bansal
> Msc Bioinformatics
> Kings College London
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