Re: [R] Drop non-integers
On Nov 17, 2010, at 6:57 PM, Sam Albers wrote:
On Wed, Nov 17, 2010 at 3:49 PM, David Winsemius > wrote:
On Nov 17, 2010, at 6:27 PM, Sam Albers wrote:
Hello all,
I have a fairly simple data manipulation question. Say I have a
dataframe
like this:
dat <- as.data.frame(runif(7, 3, 5))
dat$cat <- factor(c("1","4","13","1","4","13","13A"))
dat
runif(7, 3, 5) cat
1 3.880020 1
2 4.062800 4
3 4.828950 13
4 4.761850 1
5 4.716962 4
6 3.868348 13
7 3.420944 13A
Under the dat$cat variable the 13A value is an analytical
replicate. For my
purposes I would like to drop all values that are not an integer
(i.e. 13A)
from the dataframe. Can anyone recommend a way to drop all rows
where the
cat value is a non-integer?
DW
dat[!is.na(as.numeric(as.character(dat$cat))), ]
(You do get a warning about coercion to NA's but that is a good
sign since that is what we were trying to exclude in the first
place.)
SA---
Apologies. This worked fine but I didn't quite outline that I also
wanted to drop the unused levels of the factor as well. drop=TRUE
doesn't seem to work, so can anyone suggest a way to drop the factor
levels in addition to the values?
> sd <- dat[!is.na(as.numeric(as.character(dat$cat))), ]
Warning message:
In `[.data.frame`(dat, !is.na(as.numeric(as.character(dat$cat))), :
NAs introduced by coercion
> str(sd)
'data.frame':6 obs. of 2 variables:
$ runif(7, 3, 5): num 3.88 4.06 4.83 4.76 4.72 ...
$ cat : Factor w/ 4 levels "1","13","13A",..: 1 4 2 1 4 2
Right. Well, pretty simple actually:
dat2 <- dat[!is.na(as.numeric(as.character(dat$cat))), ]
dat2$cat <- factor(dat2$cat) # removes the no-longer-existent levels
--
David Winsemius, MD
West Hartford, CT
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Re: [R] Drop non-integers
On Wed, Nov 17, 2010 at 3:49 PM, David Winsemius wrote:
>
> On Nov 17, 2010, at 6:27 PM, Sam Albers wrote:
>
> Hello all,
>>
>> I have a fairly simple data manipulation question. Say I have a dataframe
>> like this:
>>
>> dat <- as.data.frame(runif(7, 3, 5))
>> dat$cat <- factor(c("1","4","13","1","4","13","13A"))
>>
>> dat
>> runif(7, 3, 5) cat
>> 1 3.880020 1
>> 2 4.062800 4
>> 3 4.828950 13
>> 4 4.761850 1
>> 5 4.716962 4
>> 6 3.868348 13
>> 7 3.420944 13A
>>
>> Under the dat$cat variable the 13A value is an analytical replicate. For
>> my
>> purposes I would like to drop all values that are not an integer (i.e.
>> 13A)
>> from the dataframe. Can anyone recommend a way to drop all rows where the
>> cat value is a non-integer?
>>
>
> dat[!is.na(as.numeric(as.character(dat$cat))), ]
>
> (You do get a warning about coercion to NA's but that is a good sign since
> that is what we were trying to exclude in the first place.)
>
Apologies. This worked fine but I didn't quite outline that I also wanted to
drop the unused levels of the factor as well. drop=TRUE doesn't seem to
work, so can anyone suggest a way to drop the factor levels in addition to
the values?
> sd <- dat[!is.na(as.numeric(as.character(dat$cat))), ]
Warning message:
In `[.data.frame`(dat, !is.na(as.numeric(as.character(dat$cat))), :
NAs introduced by coercion
> str(sd)
'data.frame':6 obs. of 2 variables:
$ runif(7, 3, 5): num 3.88 4.06 4.83 4.76 4.72 ...
$ cat : Factor w/ 4 levels "1","13","13A",..: 1 4 2 1 4 2
>
>
>> Sorry for the simple question and thanks in advance.
>>
>> Sam
>> --
>> *
>> Sam Albers
>> Geography Program
>> University of Northern British Columbia
>> University Way
>> Prince George, British Columbia
>> Canada, V2N 4Z9
>> phone: 250 960-6777
>> *
>>
>>[[alternative HTML version deleted]]
>>
>> __
>> R-help@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
> West Hartford, CT
>
>
--
*
Sam Albers
Geography Program
University of Northern British Columbia
University Way
Prince George, British Columbia
Canada, V2N 4Z9
phone: 250 960-6777
*
[[alternative HTML version deleted]]
__
R-help@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.
Re: [R] Drop non-integers
On 17/11/2010 6:27 PM, Sam Albers wrote:
Hello all,
I have a fairly simple data manipulation question. Say I have a dataframe
like this:
dat<- as.data.frame(runif(7, 3, 5))
dat$cat<- factor(c("1","4","13","1","4","13","13A"))
dat
runif(7, 3, 5) cat
1 3.880020 1
2 4.062800 4
3 4.828950 13
4 4.761850 1
5 4.716962 4
6 3.868348 13
7 3.420944 13A
Under the dat$cat variable the 13A value is an analytical replicate. For my
purposes I would like to drop all values that are not an integer (i.e. 13A)
from the dataframe. Can anyone recommend a way to drop all rows where the
cat value is a non-integer?
You can see if an entry is non-numeric using
nonnumeric <- is.na( as.numeric( as.character(dat$cat) ) )
With the data in your example, that test would be good enough. If you'd
also like to be able to rule out non-integers like 13.1, you could use
the lines:
value <- as.numeric( as.character(dat$cat) ) # get the numbers
noninteger <- value %% 1 != 0 # see if there's a fractional part
noninteger <- noninteger | is.na(noninteger) # get rid of the NA's
from line 1
Once you have a logical vector indicating which rows to keep, use it to
index:
dat[!noninteger,]
Duncan Murdoch
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PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
Re: [R] Drop non-integers
On Nov 17, 2010, at 6:27 PM, Sam Albers wrote:
Hello all,
I have a fairly simple data manipulation question. Say I have a
dataframe
like this:
dat <- as.data.frame(runif(7, 3, 5))
dat$cat <- factor(c("1","4","13","1","4","13","13A"))
dat
runif(7, 3, 5) cat
1 3.880020 1
2 4.062800 4
3 4.828950 13
4 4.761850 1
5 4.716962 4
6 3.868348 13
7 3.420944 13A
Under the dat$cat variable the 13A value is an analytical replicate.
For my
purposes I would like to drop all values that are not an integer
(i.e. 13A)
from the dataframe. Can anyone recommend a way to drop all rows
where the
cat value is a non-integer?
dat[!is.na(as.numeric(as.character(dat$cat))), ]
(You do get a warning about coercion to NA's but that is a good sign
since that is what we were trying to exclude in the first place.)
Sorry for the simple question and thanks in advance.
Sam
--
*
Sam Albers
Geography Program
University of Northern British Columbia
University Way
Prince George, British Columbia
Canada, V2N 4Z9
phone: 250 960-6777
*
[[alternative HTML version deleted]]
__
R-help@r-project.org mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
David Winsemius, MD
West Hartford, CT
__
R-help@r-project.org mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
[R] Drop non-integers
Hello all,
I have a fairly simple data manipulation question. Say I have a dataframe
like this:
dat <- as.data.frame(runif(7, 3, 5))
dat$cat <- factor(c("1","4","13","1","4","13","13A"))
dat
runif(7, 3, 5) cat
1 3.880020 1
2 4.062800 4
3 4.828950 13
4 4.761850 1
5 4.716962 4
6 3.868348 13
7 3.420944 13A
Under the dat$cat variable the 13A value is an analytical replicate. For my
purposes I would like to drop all values that are not an integer (i.e. 13A)
from the dataframe. Can anyone recommend a way to drop all rows where the
cat value is a non-integer?
Sorry for the simple question and thanks in advance.
Sam
--
*
Sam Albers
Geography Program
University of Northern British Columbia
University Way
Prince George, British Columbia
Canada, V2N 4Z9
phone: 250 960-6777
*
[[alternative HTML version deleted]]
__
R-help@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.
