[R] R help..subsetting data frame that meeting multiple criteria

[arun]

Hi David,
Tried the solution on a slightly different data:
dat <- read.table(text="
value class percent
15526 36 4.6875
15527 62 85.9375
15527 82 32.4564
15528 36 70.3125
15528 62 9.375
15528 82 74.6875
15529 72 50.0000
15530 72 50.0000
", header = TRUE)
dat.a <- dat[ dat[["class"]] %in% dat[ dat[["percent"]] >70, "class"] , ]
 row.names(dat.a) <- unlist(tapply(dat.a$class, dat.a$class, function(x) paste0(x, letters[1:length(x)])))
 dat.a
#    value class percent
#36a 15526    36  4.6875
#36b 15527    62 85.9375
#62a 15527    82 32.4564
#62b 15528    36 70.3125
#82a 15528    62  9.3750
#82b 15528    82 74.6875


A.K.




----- Original Message -----
From: David Winsemius <dwinsemius at comcast.net>
To: prasmas <prasad4rr at gmail.com>
Cc: r-help at r-project.org
Sent: Friday, November 23, 2012 7:40 PM
Subject: Re: [R] R help..subsetting data frame that meeting multiple criteria


On Nov 23, 2012, at 1:14 PM, prasmas wrote:

> Hi,
> I am new to R.  I am trying to regroup data frame using multiple constrains.
> for example
> 
> data frame: data
>  value    class    percent
> 15526    36    4.6875
> 15527    62    85.9375
> 15527    82    32.4564
> 15528    36    70.3125
> 15528    62    9.375
> 15528    82    74.6875
> 
> I need to regroup each class that have greater than or equal to 70 percent
> into new group. Similarly, I also need to regroup each class that have less
> than 70 percent into new group.
> 
> I can do this by using following syntax for each class
> class36<- data[data$class==36&data$percent>70,]
> class36a<- data[data$class==36&data$percent<=70,]
> but I have 100 different classes. In order to do this for all 100 classes, I
> have write that syntax 100 times. There would be some way to do dynamically
> to regroup for 100 classes (may be using for loop) but I dont know. Can you
> please help in this.
> Output should be like
> data frame: class36
> value    class    percent
> 15528    36    70.3125
> 
> data frame: class36a
> value    class    percent
> 15526    36    4.6875
> 
> dat.a <- dat[ dat[["class"]] %in% dat[ dat[["percent"]] >70, "class"] , ]
> dat.a
  value class percent
1 15526    36  4.6875
2 15527    62 85.9375
3 15527    82 32.4564
4 15528    36 70.3125
5 15528    62  9.3750
6 15528    82 74.6875

> row.names(dat.a) <- unlist(tapply(dat.a$class, dat.a$class, function(x) paste0(x, letters[1:length(x)])))
> dat.a
    value class percent
36a 15526    36  4.6875
36b 15527    62 85.9375
62a 15527    82 32.4564
62b 15528    36 70.3125
82a 15528    62  9.3750
82b 15528    82 74.6875

You can split by the NROW of dat.a if you want.

--David.
>
> data frame: class62
> 15527    62    85.9375
> 
> data frame: class62a
> 15528    62    9.375
> 
> data frame: class82
> 15528    82    74.6875
> 
> data frame: class82a
> 15527    82    32.4564
> 
> Thank you very much your help..
> P.
> 
> 
> 
> --
> View this message in context: http://r.789695.n4.nabble.com/R-help-subsetting-data-frame-that-meeting-multiple-criteria-tp4650601.html
> Sent from the R help mailing list archive at Nabble.com.
> 
> ______________________________________________
> 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.

David Winsemius, MD
Alameda, CA, USA

______________________________________________
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