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Apply a function according to factor levels.

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li li-13

Apply a function according to factor levels.

Dear all,
I have a question on applying a function to the data according to factor
levels.
For example, for the data below, what is the best way to apply a function
to
"values" according to different levels of "samples" (1,2,3,4,5)?
values ind sample
1 0.03325 1 1
2 0.03305 1 1
3 0.03185 1 1
4 0.03515 1 1
5 0.03375 1 1
6 0.01180 1 2
7 0.01850 1 3
8 0.02915 1 4
9 0.06200 1 5
10 0.03230 2 1
11 0.03345 2 1
12 0.03385 2 1
13 0.03605 2 1
14 0.03225 2 1
15 0.01145 2 2
16 0.01805 2 3
17 0.02950 2 4
18 0.05995 2 5
19 0.03425 3 1
20 0.03575 3 1
21 0.03535 3 1
22 0.03380 3 1
23 0.03410 3 1
24 0.01050 3 2
25 0.01735 3 3
26 0.03140 3 4
27 0.06170 3 5
28 0.03430 4 1
29 0.03185 4 1
30 0.03165 4 1
31 0.03380 4 1
32 0.03235 4 1
33 0.01100 4 2
34 0.01825 4 3
35 0.03045 4 4
36 0.06060 4 5
37 0.03280 5 1
38 0.03350 5 1
39 0.03215 5 1
40 0.03545 5 1
41 0.03285 5 1
42 0.01085 5 2
43 0.01660 5 3
44 0.03060 5 4
45 0.06605 5 5

Thank you.
Hannah

[[alternative HTML version deleted]]

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David Carlson

Re: Apply a function according to factor levels.

?tapply

----------------------------------------------
David L Carlson
Associate Professor of Anthropology
Texas A&M University
College Station, TX 77843-4352

> -----Original Message-----
> From: [hidden email] [mailto:r-help-bounces@r-
> project.org] On Behalf Of li li
> Sent: Thursday, August 16, 2012 8:31 PM
> To: r-help
> Subject: [R] Apply a function according to factor levels.
>
> Dear all,
> I have a question on applying a function to the data according to
> factor
> levels.
> For example, for the data below, what is the best way to apply a
> function
> to
> "values" according to different levels of "samples" (1,2,3,4,5)?
> values ind sample
> 1 0.03325 1 1
> 2 0.03305 1 1
> 3 0.03185 1 1
> 4 0.03515 1 1
> 5 0.03375 1 1
> 6 0.01180 1 2
> 7 0.01850 1 3
> 8 0.02915 1 4
> 9 0.06200 1 5
> 10 0.03230 2 1
> 11 0.03345 2 1
> 12 0.03385 2 1
> 13 0.03605 2 1
> 14 0.03225 2 1
> 15 0.01145 2 2
> 16 0.01805 2 3
> 17 0.02950 2 4
> 18 0.05995 2 5
> 19 0.03425 3 1
> 20 0.03575 3 1
> 21 0.03535 3 1
> 22 0.03380 3 1
> 23 0.03410 3 1
> 24 0.01050 3 2
> 25 0.01735 3 3
> 26 0.03140 3 4
> 27 0.06170 3 5
> 28 0.03430 4 1
> 29 0.03185 4 1
> 30 0.03165 4 1
> 31 0.03380 4 1
> 32 0.03235 4 1
> 33 0.01100 4 2
> 34 0.01825 4 3
> 35 0.03045 4 4
> 36 0.06060 4 5
> 37 0.03280 5 1
> 38 0.03350 5 1
> 39 0.03215 5 1
> 40 0.03545 5 1
> 41 0.03285 5 1
> 42 0.01085 5 2
> 43 0.01660 5 3
> 44 0.03060 5 4
> 45 0.06605 5 5
>
>
> Thank you.
> Hannah
>
> [[alternative HTML version deleted]]
>
> ______________________________________________
> [hidden email] 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.

______________________________________________
[hidden email] 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.

Rui Barradas

Re: Apply a function according to factor levels.

Hello,

Or ?aggregate, depending on the wanted output. With the dataset provided
by the op, apply function mean.

dat <- read.table(text="
values ind sample
1 0.03325 1 1
2 0.03305 1 1
3 0.03185 1 1
[...etc...]
44 0.03060 5 4
45 0.06605 5 5
", header = TRUE)

tapply(dat$values, dat$sample, mean) # named vector
1 2 3 4 5
0.033556 0.011120 0.017750 0.030220 0.062060

aggregate(values ~ sample, data = dat, mean) # data.frame
sample values
1 1 0.033556
2 2 0.011120
3 3 0.017750
4 4 0.030220
5 5 0.062060

Hope this helps,

Rui Barradas

Em 17-08-2012 02:41, David L Carlson escreveu:

> ?tapply
>
> ----------------------------------------------
> David L Carlson
> Associate Professor of Anthropology
> Texas A&M University
> College Station, TX 77843-4352
>
>
>> -----Original Message-----
>> From: [hidden email] [mailto:r-help-bounces@r-
>> project.org] On Behalf Of li li
>> Sent: Thursday, August 16, 2012 8:31 PM
>> To: r-help
>> Subject: [R] Apply a function according to factor levels.
>>
>> Dear all,
>> I have a question on applying a function to the data according to
>> factor
>> levels.
>> For example, for the data below, what is the best way to apply a
>> function
>> to
>> "values" according to different levels of "samples" (1,2,3,4,5)?
>> values ind sample
>> 1 0.03325 1 1
>> 2 0.03305 1 1
>> 3 0.03185 1 1
>> 4 0.03515 1 1
>> 5 0.03375 1 1
>> 6 0.01180 1 2
>> 7 0.01850 1 3
>> 8 0.02915 1 4
>> 9 0.06200 1 5
>> 10 0.03230 2 1
>> 11 0.03345 2 1
>> 12 0.03385 2 1
>> 13 0.03605 2 1
>> 14 0.03225 2 1
>> 15 0.01145 2 2
>> 16 0.01805 2 3
>> 17 0.02950 2 4
>> 18 0.05995 2 5
>> 19 0.03425 3 1
>> 20 0.03575 3 1
>> 21 0.03535 3 1
>> 22 0.03380 3 1
>> 23 0.03410 3 1
>> 24 0.01050 3 2
>> 25 0.01735 3 3
>> 26 0.03140 3 4
>> 27 0.06170 3 5
>> 28 0.03430 4 1
>> 29 0.03185 4 1
>> 30 0.03165 4 1
>> 31 0.03380 4 1
>> 32 0.03235 4 1
>> 33 0.01100 4 2
>> 34 0.01825 4 3
>> 35 0.03045 4 4
>> 36 0.06060 4 5
>> 37 0.03280 5 1
>> 38 0.03350 5 1
>> 39 0.03215 5 1
>> 40 0.03545 5 1
>> 41 0.03285 5 1
>> 42 0.01085 5 2
>> 43 0.01660 5 3
>> 44 0.03060 5 4
>> 45 0.06605 5 5
>>
>>
>> Thank you.
>> Hannah
>>
>> [[alternative HTML version deleted]]
>>
>> ______________________________________________
>> [hidden email] 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.
> ______________________________________________
> [hidden email] 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.

arun kirshna

Re: Apply a function according to factor levels.

In reply to this post by li li-13

Hi,
Try this:
dat1<-read.table(text="
no.   values ind sample
1 0.03325 1      1
2 0.03305 1      1
3 0.03185 1      1
4 0.03515 1      1

-------------------------
-------------------------
42 0.01085 5      2
43 0.01660 5      3
44 0.03060 5      4
45 0.06605 5      5
",sep="",header=TRUE)
dat2<-within(dat1,{sample<-as.factor(sample)})
ddply(dat2,.(sample), function(x) mean(x$values))
# sample       V1
#1      1 0.033556
#2      2 0.011120
#3      3 0.017750
#4      4 0.030220
#5      5 0.062060
A.K.

----- Original Message -----
From: li li <[hidden email]>
To: r-help <[hidden email]>
Cc:
Sent: Thursday, August 16, 2012 9:31 PM
Subject: [R] Apply a function according to factor levels.

Dear all,
I have a question on applying a function to the data according to factor
levels.
For example, for the data below, what is the best way to apply a function
to
"values" according to different levels of "samples" (1,2,3,4,5)?
values ind sample
1 0.03325 1 1
2 0.03305 1 1
3 0.03185 1 1
4 0.03515 1 1
5 0.03375 1 1
6 0.01180 1 2
7 0.01850 1 3
8 0.02915 1 4
9 0.06200 1 5
10 0.03230 2 1
11 0.03345 2 1
12 0.03385 2 1
13 0.03605 2 1
14 0.03225 2 1
15 0.01145 2 2
16 0.01805 2 3
17 0.02950 2 4
18 0.05995 2 5
19 0.03425 3 1
20 0.03575 3 1
21 0.03535 3 1
22 0.03380 3 1
23 0.03410 3 1
24 0.01050 3 2
25 0.01735 3 3
26 0.03140 3 4
27 0.06170 3 5
28 0.03430 4 1
29 0.03185 4 1
30 0.03165 4 1
31 0.03380 4 1
32 0.03235 4 1
33 0.01100 4 2
34 0.01825 4 3
35 0.03045 4 4
36 0.06060 4 5
37 0.03280 5 1
38 0.03350 5 1
39 0.03215 5 1
40 0.03545 5 1
41 0.03285 5 1
42 0.01085 5 2
43 0.01660 5 3
44 0.03060 5 4
45 0.06605 5 5

Thank you.
Hannah

    [[alternative HTML version deleted]]

______________________________________________
[hidden email] 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.

______________________________________________
[hidden email] 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.

li li-13

Re: Apply a function according to factor levels.

Got it. Thanks so much.
Hannah

2012/8/16 arun <[hidden email]>

> Hi,
> Try this:
> dat1<-read.table(text="
> no. values ind sample
> 1 0.03325 1 1
> 2 0.03305 1 1
> 3 0.03185 1 1
> 4 0.03515 1 1
>
> -------------------------
> -------------------------
> 42 0.01085 5 2
> 43 0.01660 5 3
> 44 0.03060 5 4
> 45 0.06605 5 5
> ",sep="",header=TRUE)
> dat2<-within(dat1,{sample<-as.factor(sample)})
> ddply(dat2,.(sample), function(x) mean(x$values))
> # sample V1
> #1 1 0.033556
> #2 2 0.011120
> #3 3 0.017750
> #4 4 0.030220
> #5 5 0.062060
> A.K.
>
> ----- Original Message -----
> From: li li <[hidden email]>
> To: r-help <[hidden email]>
> Cc:
> Sent: Thursday, August 16, 2012 9:31 PM
> Subject: [R] Apply a function according to factor levels.
>
> Dear all,
> I have a question on applying a function to the data according to factor
> levels.
> For example, for the data below, what is the best way to apply a function
> to
> "values" according to different levels of "samples" (1,2,3,4,5)?
> values ind sample
> 1 0.03325 1 1
> 2 0.03305 1 1
> 3 0.03185 1 1
> 4 0.03515 1 1
> 5 0.03375 1 1
> 6 0.01180 1 2
> 7 0.01850 1 3
> 8 0.02915 1 4
> 9 0.06200 1 5
> 10 0.03230 2 1
> 11 0.03345 2 1
> 12 0.03385 2 1
> 13 0.03605 2 1
> 14 0.03225 2 1
> 15 0.01145 2 2
> 16 0.01805 2 3
> 17 0.02950 2 4
> 18 0.05995 2 5
> 19 0.03425 3 1
> 20 0.03575 3 1
> 21 0.03535 3 1
> 22 0.03380 3 1
> 23 0.03410 3 1
> 24 0.01050 3 2
> 25 0.01735 3 3
> 26 0.03140 3 4
> 27 0.06170 3 5
> 28 0.03430 4 1
> 29 0.03185 4 1
> 30 0.03165 4 1
> 31 0.03380 4 1
> 32 0.03235 4 1
> 33 0.01100 4 2
> 34 0.01825 4 3
> 35 0.03045 4 4
> 36 0.06060 4 5
> 37 0.03280 5 1
> 38 0.03350 5 1
> 39 0.03215 5 1
> 40 0.03545 5 1
> 41 0.03285 5 1
> 42 0.01085 5 2
> 43 0.01660 5 3
> 44 0.03060 5 4
> 45 0.06605 5 5
>
>
> Thank you.
> Hannah
>
> [[alternative HTML version deleted]]
>
> ______________________________________________
> [hidden email] mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide
> http://www.R-project.org/posting-guide.html<http://www.r-project.org/posting-guide.html>
> and provide commented, minimal, self-contained, reproducible code.
>
>

[[alternative HTML version deleted]]

______________________________________________
[hidden email] 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.