[R] detecting null values in a CSV file

[jim holtman]

You can always do this if they are single valued vectors:

if ((!is.na(data_filter)) & (!is.na(trigger)) & (data_filter == trigger)) ....

This will catch the condition where either is an NA and therefore not
do the final compare which was giving your error.

On Fri, Sep 19, 2008 at 9:48 AM, Jason Thibodeau <jbloudg20 at gmail.com> wrote:
> On a related note, I am trying to do some matching using conditional
> statements. These NULL values are being brought in to my data frame as NA,
> as expected, but in a conditional if() statement, I cannot compare then to a
> integer value, it fails the program. Here is a small snippet of where the
> error occurs.
>
>  while(col_loop<1570)
>                        {
>                                data_filter <- data[c(col_loop)]
>                                print(data_filter)
>                                if(data_filter == trigger)
>                                {
>                                        trigger_count <- trigger_count +1
>                                }
>                                col_loop <- col_loop +1
>
>                        }
>
> Here: trigger_count, and trigger are both integers. The print statement was
> debug to see why it was failing and this is what it returned:
> <snip>
>  V1415
> 1     0
>  V1416
> 1     0
>  V1417
> 1     1
>  V1418
> 1     1
>  V1419
> 1     1
>  V1420
> 1    NA
> Error in if (data_filter == trigger) { :
>  missing value where TRUE/FALSE needed
>
> Thanks for any help you can provide.
>
> On Thu, Sep 18, 2008 at 2:12 PM, Hutchinson,David [PYR] <
> David.Hutchinson at ec.gc.ca> wrote:
>
>> Try length(na.omit(<the particular data column>))
>>
>> Here's an example:
>>
>> data <- runif(100,0,10)
>> data[runif(20,0,100)] <- NA
>> file.contents <- matrix(data, ncol = 5, byrow = TRUE)
>> for (i in 1:5) {
>>  print (length(na.omit(file.contents[,i])))
>> }
>>
>>
>> -----Original Message-----
>> From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-project.org]
>> On Behalf Of Jason Thibodeau
>> Sent: Thursday, September 18, 2008 10:12 AM
>> To: r-help at r-project.org
>> Subject: [R] detecting null values in a CSV file
>>
>> Hello all,
>>
>> I have a CSV file, that is 2411 columns wide. There are certain
>> instances in
>> teh file, where null values are located. That is: two commas together,
>> without anything in the middle. In a certain section, the only possible
>> values are NULL, 0,1,and 2. I need to be able to detect these NULL's and
>> be
>> able to have them counted. For example, in a frequency table. How can I
>> accomplish this?
>>
>> Thanks in advance for the help.
>>
>> --
>> Jason Thibodeau
>>
>>         [[alternative HTML version deleted]]
>>
>> ______________________________________________
>> 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.
>>
>
>
>
> --
> Jason Thibodeau
>
>        [[alternative HTML version deleted]]
>
> ______________________________________________
> 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
Cincinnati, OH
+1 513 646 9390

What is the problem that you are trying to solve?