[R] Accessing items in a list of lists
Using R 2.6.2, say I have the following list of lists, comb:
data1 - list(a = 1, b = 2, c = 3)
data2 - list(a = 4, b = 5, c = 6)
data3 - list(a = 3, b = 6, c = 9)
comb - list(data1 = data1, data2 = data2, data3 = data3)
So that all names for the lowest level list are common. How can I most
efficiently access all of the sublist items a indexed by the outer
list names? For example, I can loop through comb[[i]], unlisting as I
go, and then look up the field a, as below, but there has got to be a
cleaner way.
finaldata - double(0)
for(i in 1:length(names(comb))) {
test - unlist(comb[[i]])
finaldata - c(finaldata, test[which(names(test) == a)])
}
data.frame(names(comb), finaldata)
Gives what I want:
names.comb. finaldata
1 data1 1
2 data2 4
3 data3 3
Any help you can give would be greatly appreciated. Thanks.
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Re: [R] Accessing items in a list of lists
Try this:
do.call(rbind, lapply(comb, '[', 'a'))
On Wed, May 14, 2008 at 4:40 PM, [EMAIL PROTECTED]
wrote:
Using R 2.6.2, say I have the following list of lists, comb:
data1 - list(a = 1, b = 2, c = 3)
data2 - list(a = 4, b = 5, c = 6)
data3 - list(a = 3, b = 6, c = 9)
comb - list(data1 = data1, data2 = data2, data3 = data3)
So that all names for the lowest level list are common. How can I most
efficiently access all of the sublist items a indexed by the outer
list names? For example, I can loop through comb[[i]], unlisting as I
go, and then look up the field a, as below, but there has got to be a
cleaner way.
finaldata - double(0)
for(i in 1:length(names(comb))) {
test - unlist(comb[[i]])
finaldata - c(finaldata, test[which(names(test) == a)])
}
data.frame(names(comb), finaldata)
Gives what I want:
names.comb. finaldata
1 data1 1
2 data2 4
3 data3 3
Any help you can give would be greatly appreciated. Thanks.
This information is being sent at the recipient's reques...{{dropped:16}}
__
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and provide commented, minimal, self-contained, reproducible code.
--
Henrique Dallazuanna
Curitiba-Paraná-Brasil
25° 25' 40 S 49° 16' 22 O
[[alternative HTML version deleted]]
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Re: [R] Accessing items in a list of lists
Try this:
data1 - list(a = 1, b = 2, c = 3)
data2 - list(a = 4, b = 5, c = 6)
data3 - list(a = 3, b = 6, c = 9)
comb - list(data1 = data1, data2 = data2, data3 = data3)
sapply(comb, [[, a)
data1 data2 data3
1 4 3
# Also, this can be useful:
comb[[c(data2, b)]]
[1] 5
[EMAIL PROTECTED] wrote:
Using R 2.6.2, say I have the following list of lists, comb:
data1 - list(a = 1, b = 2, c = 3)
data2 - list(a = 4, b = 5, c = 6)
data3 - list(a = 3, b = 6, c = 9)
comb - list(data1 = data1, data2 = data2, data3 = data3)
So that all names for the lowest level list are common. How can I most
efficiently access all of the sublist items a indexed by the outer
list names? For example, I can loop through comb[[i]], unlisting as I
go, and then look up the field a, as below, but there has got to be a
cleaner way.
finaldata - double(0)
for(i in 1:length(names(comb))) {
test - unlist(comb[[i]])
finaldata - c(finaldata, test[which(names(test) == a)])
}
data.frame(names(comb), finaldata)
Gives what I want:
names.comb. finaldata
1 data1 1
2 data2 4
3 data3 3
Any help you can give would be greatly appreciated. Thanks.
This information is being sent at the recipient's reques...{{dropped:16}}
__
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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.
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Re: [R] Accessing items in a list of lists
[EMAIL PROTECTED] said the following on 5/14/2008
12:40 PM:
Using R 2.6.2, say I have the following list of lists, comb:
data1 - list(a = 1, b = 2, c = 3)
data2 - list(a = 4, b = 5, c = 6)
data3 - list(a = 3, b = 6, c = 9)
comb - list(data1 = data1, data2 = data2, data3 = data3)
So that all names for the lowest level list are common. How can I most
efficiently access all of the sublist items a indexed by the outer
list names? For example, I can loop through comb[[i]], unlisting as I
go, and then look up the field a, as below, but there has got to be a
cleaner way.
finaldata - double(0)
for(i in 1:length(names(comb))) {
test - unlist(comb[[i]])
finaldata - c(finaldata, test[which(names(test) == a)])
}
data.frame(names(comb), finaldata)
Gives what I want:
names.comb. finaldata
1 data1 1
2 data2 4
3 data3 3
Any help you can give would be greatly appreciated. Thanks.
Try
data.frame(names.comb = names(comb),
finaldata = sapply(comb, [[, a))
HTH,
--sundar
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Re: [R] Accessing items in a list of lists
check the following:
sapply(comb, [[, a)
# or
data.frame(
names = names(comb),
value = sapply(comb, [[, a),
row.names = seq_along(comb)
)
I hope it helps.
Best,
Dimitris
Dimitris Rizopoulos
Biostatistical Centre
School of Public Health
Catholic University of Leuven
Address: Kapucijnenvoer 35, Leuven, Belgium
Tel: +32/(0)16/336899
Fax: +32/(0)16/337015
Web: http://med.kuleuven.be/biostat/
http://www.student.kuleuven.be/~m0390867/dimitris.htm
Quoting [EMAIL PROTECTED]:
Using R 2.6.2, say I have the following list of lists, comb:
data1 - list(a = 1, b = 2, c = 3)
data2 - list(a = 4, b = 5, c = 6)
data3 - list(a = 3, b = 6, c = 9)
comb - list(data1 = data1, data2 = data2, data3 = data3)
So that all names for the lowest level list are common. How can I most
efficiently access all of the sublist items a indexed by the outer
list names? For example, I can loop through comb[[i]], unlisting as I
go, and then look up the field a, as below, but there has got to be a
cleaner way.
finaldata - double(0)
for(i in 1:length(names(comb))) {
test - unlist(comb[[i]])
finaldata - c(finaldata, test[which(names(test) == a)])
}
data.frame(names(comb), finaldata)
Gives what I want:
names.comb. finaldata
1 data1 1
2 data2 4
3 data3 3
Any help you can give would be greatly appreciated. Thanks.
This information is being sent at the recipient's reques...{{dropped:16}}
__
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.
Disclaimer: http://www.kuleuven.be/cwis/email_disclaimer.htm
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