R help - May 2022 - extracting numeric values returned when using the by function to run the acf function

I am using the by function to run the acf function. Each run of the by function
returns more information than I want. All I want is the four values that acf
returns, which using the data below would be
1.00  0.15   -0.50  -0.15
How  can I isolate these four values from the output returned by the by
function.

Sample code:

RecallSmall <- data.frame(ID=c(1,1,1,1),value=c(6,5,3,4))
cat("Here are the data\n")
RecallSmall
cat("All I want is autocorrerlations, e.g. 1.00  0.15 -0.50 -0.15 \n
")
# attempting to subset does not work at all
by(RecallSmall[1:4,"value"],RecallSmall[1:4,"ID"],acf,na.action=na.pass,plot=FALSE)$acf
# this gives me more than I want, not just the numeric results.
by(RecallSmall[1:4,"value"],RecallSmall[1:4,"ID"],acf,na.action=na.pass,plot=FALSE)

# For your reference, this is what the acf function returns
acf(RecallSmall[1:4,"value"],na.action=na.pass,plot=FALSE)
# For your reference, this is what the acf function returns when the output is
subset
acf(RecallSmall[1:4,"value"],na.action=na.pass,plot=FALSE)Thank you,
John

Thank you,
John









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Hello,

by returns an object of class "by" that inherits from class
"list". So
assign its return value and then use sapply to extract the list members 
you want.


RecallSmall <- data.frame(ID=c(1,1,1,1),value=c(6,5,3,4))

acf_list <- 
by(RecallSmall[1:4,"value"],RecallSmall[1:4,"ID"],acf,na.action=na.pass,plot=FALSE)
sapply(acf_list, `[[`, 1)
#>          1
#> [1,]  1.00
#> [2,]  0.15
#> [3,] -0.50
#> [4,] -0.15


This can be coerced to vector with c().

Hope this helps,

Rui Barradas

?s 18:29 de 10/05/2022, Sorkin, John escreveu:
> I am using the by function to run the acf function. Each run of the by
function returns more information than I want. All I want is the four values
that acf returns, which using the data below would be
> 1.00  0.15   -0.50  -0.15
> How  can I isolate these four values from the output returned by the by
function.
> 
> Sample code:
> 
> RecallSmall <- data.frame(ID=c(1,1,1,1),value=c(6,5,3,4))
> cat("Here are the data\n")
> RecallSmall
> cat("All I want is autocorrerlations, e.g. 1.00  0.15 -0.50 -0.15 \n
")
> # attempting to subset does not work at all
>
by(RecallSmall[1:4,"value"],RecallSmall[1:4,"ID"],acf,na.action=na.pass,plot=FALSE)$acf
> # this gives me more than I want, not just the numeric results.
>
by(RecallSmall[1:4,"value"],RecallSmall[1:4,"ID"],acf,na.action=na.pass,plot=FALSE)
> 
> # For your reference, this is what the acf function returns
> acf(RecallSmall[1:4,"value"],na.action=na.pass,plot=FALSE)
> # For your reference, this is what the acf function returns when the output
is subset
> acf(RecallSmall[1:4,"value"],na.action=na.pass,plot=FALSE)Thank
you, John
> 
> Thank you,
> John
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 	[[alternative HTML version deleted]]
> 
> ______________________________________________
> R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see
> 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.

as.numeric(by(RecallSmall[1:4,"value"],RecallSmall[1:4,"ID"],acf,na.action=na.pass,plot=FALSE)[[1]]$acf)


On Tue, May 10, 2022 at 8:29 PM Sorkin, John <jsorkin at
som.umaryland.edu>
wrote:
> I am using the by function to run the acf function. Each run of the by
> function returns more information than I want. All I want is the four
> values that acf returns, which using the data below would be
> 1.00  0.15   -0.50  -0.15
> How  can I isolate these four values from the output returned by the by
> function.
>
> Sample code:
>
> RecallSmall <- data.frame(ID=c(1,1,1,1),value=c(6,5,3,4))
> cat("Here are the data\n")
> RecallSmall
> cat("All I want is autocorrerlations, e.g. 1.00  0.15 -0.50 -0.15 \n
")
> # attempting to subset does not work at all
>
>
by(RecallSmall[1:4,"value"],RecallSmall[1:4,"ID"],acf,na.action=na.pass,plot=FALSE)$acf
> # this gives me more than I want, not just the numeric results.
>
>
by(RecallSmall[1:4,"value"],RecallSmall[1:4,"ID"],acf,na.action=na.pass,plot=FALSE)
>
> # For your reference, this is what the acf function returns
> acf(RecallSmall[1:4,"value"],na.action=na.pass,plot=FALSE)
> # For your reference, this is what the acf function returns when the
> output is subset
> acf(RecallSmall[1:4,"value"],na.action=na.pass,plot=FALSE)Thank
you, John
>
> Thank you,
> John
>
>
>
>
>
>
>
>
>
>         [[alternative HTML version deleted]]
>
> ______________________________________________
> R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see
> 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.
>
	[[alternative HTML version deleted]]

Hi,

You can either write a small function that returns just the values you
want, or use a convenience function within by, as in:
> by(RecallSmall[1:4,"value"],RecallSmall[1:4,"ID"],
FUN=function(x){acf(x, na.action=na.pass,plot=FALSE)$acf})
RecallSmall[1:4, "ID"]: 1
, , 1

      [,1]
[1,]  1.00
[2,]  0.15
[3,] -0.50
[4,] -0.15

But I suspect that you would get something more like what you want by
splitting the data on ID, and then using sapply:
> RecallSmall <- data.frame(ID=c(1,1,1,1,2,2,2,2),
value=c(6,5,3,4,6,5,3,4))
> result <- split(RecallSmall[["value"]],
RecallSmall[["ID"]])
> result <- sapply(result, FUN=function(x){acf(x,
na.action=na.pass,plot=FALSE)$acf})
> result
         1     2
[1,]  1.00  1.00
[2,]  0.15  0.15
[3,] -0.50 -0.50
[4,] -0.15 -0.15


Sarah

On Tue, May 10, 2022 at 1:29 PM Sorkin, John <jsorkin at
som.umaryland.edu> wrote:
>
> I am using the by function to run the acf function. Each run of the by
function returns more information than I want. All I want is the four values
that acf returns, which using the data below would be
> 1.00  0.15   -0.50  -0.15
> How  can I isolate these four values from the output returned by the by
function.
>
> Sample code:
>
> RecallSmall <- data.frame(ID=c(1,1,1,1),value=c(6,5,3,4))
> cat("Here are the data\n")
> RecallSmall
> cat("All I want is autocorrerlations, e.g. 1.00  0.15 -0.50 -0.15 \n
")
> # attempting to subset does not work at all
>
by(RecallSmall[1:4,"value"],RecallSmall[1:4,"ID"],acf,na.action=na.pass,plot=FALSE)$acf
> # this gives me more than I want, not just the numeric results.
>
by(RecallSmall[1:4,"value"],RecallSmall[1:4,"ID"],acf,na.action=na.pass,plot=FALSE)
>
> # For your reference, this is what the acf function returns
> acf(RecallSmall[1:4,"value"],na.action=na.pass,plot=FALSE)
> # For your reference, this is what the acf function returns when the output
is subset
> acf(RecallSmall[1:4,"value"],na.action=na.pass,plot=FALSE)Thank
you, John
>
> Thank you,
> John
>
>
>
>
>
>
>
>
>
>         [[alternative HTML version deleted]]
>
> ______________________________________________
> R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see
> 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.


-- 
Sarah Goslee (she/her)
http://www.numberwright.com

John,
What is returned is a specialized list structure called a 'by" and
getting the part you want out can be done?sort of carefully and sometimes with a
bit of trial and error as the contents are nested. You can use?str(0 and other
tools but this seems to work with care as you need [[]] not just [] to get the
internal?contents, not another list:
> byeby <-
by(RecallSmall[1:4,"value"],RecallSmall[1:4,"ID"],acf,na.action=na.pass,plot=FALSE)
> result <- byeby[[1]]$acf
> print(result)
, , 1
? ? ? [,1][1,]? 1.00[2,]? 0.15[3,] -0.50[4,] -0.15
To make it a more normal vector rather than an array you might want to do
this.
> result <- as.vector(result)
> result
[1]? 1.00? 0.15 -0.50 -0.15

Again, we discourage use of packages here for some reason but there are many
alternatives?to using by() that get around this issue by not producing a
specialized class as output.?
And a review ofthe help page for by() shows you could have added simplify=TRUE
to make a normal?list as in:

by(RecallSmall[1:4,"value"],RecallSmall[1:4,"ID"],acf,na.action=na.pass,plot=FALSE,
simplify=TRUE)


But it remains a nested list and getting the part you want in one long command
line that works for me is:

by(RecallSmall[1:4,"value"],RecallSmall[1:4,"ID"],acf,na.action=na.pass,plot=FALSE,
simplify=TRUE)[[1]]$acf[1:4]



-----Original Message-----
From: Sorkin, John <jsorkin at som.umaryland.edu>
To: r-help at r-project.org (r-help at r-project.org) <r-help at
r-project.org>
Sent: Tue, May 10, 2022 1:29 pm
Subject: [R] extracting numeric values returned when using the by function to
run the acf function

I am using the by function to run the acf function. Each run of the by function
returns more information than I want. All I want is the four values that acf
returns, which using the data below would be
1.00? 0.15? -0.50? -0.15
How? can I isolate these four values from the output returned by the by
function.

Sample code:

RecallSmall <- data.frame(ID=c(1,1,1,1),value=c(6,5,3,4))
cat("Here are the data\n")
RecallSmall
cat("All I want is autocorrerlations, e.g. 1.00? 0.15 -0.50 -0.15 \n
")
# attempting to subset does not work at all
by(RecallSmall[1:4,"value"],RecallSmall[1:4,"ID"],acf,na.action=na.pass,plot=FALSE)$acf
# this gives me more than I want, not just the numeric results.
by(RecallSmall[1:4,"value"],RecallSmall[1:4,"ID"],acf,na.action=na.pass,plot=FALSE)

# For your reference, this is what the acf function returns
acf(RecallSmall[1:4,"value"],na.action=na.pass,plot=FALSE)
# For your reference, this is what the acf function returns when the output is
subset
acf(RecallSmall[1:4,"value"],na.action=na.pass,plot=FALSE)Thank you,
John

Thank you,
John









??? [[alternative HTML version deleted]]

______________________________________________
R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see
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.

	[[alternative HTML version deleted]]