[R] subset dataframe by rows using character vector?

[baptiste auguie]

glad it was helpful.

%in% is a logical operator, so you can use "!" to negate the result  
(with parentheses),

! ( 4 %in% 1:3)

Alternatively, define a new operator,

`%ni%` <- Negate(`%in%`)

1 %ni% c(2,1)

Next time you ask a follow-up question please send it to the r-help  
list so others can help you too.

HTH,

baptiste

On 14 Apr 2009, at 16:03, zack holden wrote:

>
> Yes! that's it. Any chance you can tell me how to select everything  
> but those plotNames? Basically a reverse subset? I don't know these  
> character matching functions very well.
>
> I very much appreciate your help, thanks again.
>
> Zack
>
> ----------------------------------------
>> CC: r-help at r-project.org
>> From: ba208 at exeter.ac.uk
>> To: zack_holden at hotmail.com
>> Subject: Re: [R] subset dataframe by rows using character vector?
>> Date: Tue, 14 Apr 2009 15:56:45 +0100
>>
>> Is this what you want?
>>
>> plotNames <- c("plot1", "plot2", "plot3") # plot is probably best
>> left as the name of the base function
>> full.data[full.data$PLOTID %in% plotNames, ] # note the comma
>>
>>
>> HTH,
>>
>> baptiste
>>
>> On 14 Apr 2009, at 15:20, zack holden wrote:
>>
>>>
>>> Dear List,
>>>
>>> I'm stuck on what seems like a simple indexing problem, I'd be very
>>> grateful to anyone willing to help me out.
>>>
>>> I queried a dataframe which returns a character vector called
>>> "plot". I have another dataframe from which I want to subset or
>>> select only those rows that match "plot". I've tried subset, and
>>> also the "which" command.
>>>
>>>
>>> plot <- c("plot1", "plot2", "plot3") # character
>>> vector used to select rows from data
>>>
>>> # create fake data from to try out subset
>>> v1 <- c(2,5,6,4,3)
>>> PLOTID <- c("plot1", "plot2", "plot3", "plot4", "plot5")
>>> full.data <- cbind(v1, PLOTID)
>>> full.data <- as.data.frame(full.data)
>>>
>>> # first attempt
>>> test <- which(full.data$PLOTID == plot)
>>>
>>> # second attempt
>>> test <- full.data[full.data$PLOTID == plot]
>>>
>>>
>>> I'm sure there is a simple solution here, but I'm unable to figure
>>> it out.
>>>
>>> Thanks for any suggestions,
>>>
>>> Zack
>>> ______________________________________________
>>> 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.
>>
>> _____________________________
>>
>> Baptiste Auguié
>>
>> School of Physics
>> University of Exeter
>> Stocker Road,
>> Exeter, Devon,
>> EX4 4QL, UK
>>
>> Phone: +44 1392 264187
>>
>> http://newton.ex.ac.uk/research/emag
>> ______________________________
>>

_____________________________

Baptiste Auguié

School of Physics
University of Exeter
Stocker Road,
Exeter, Devon,
EX4 4QL, UK

Phone: +44 1392 264187

http://newton.ex.ac.uk/research/emag