[R] turning a list of vectors into a data.frame (as rows of the DF)?
As a newer R practicioner, it seems I stump myself weekly (at least) with issues that have spinning my wheels. Here is yet another... I'm trying to turn a list of numeric vectors (of uneual length) inot a dataframe. Each vector held in the list represents a row, and there are some rows of unequal length. I would like NAs as placeholders for missing data in the shorter vectors. I think I'm missing something quite basic. v1 - c(1,2,3,4) v2 - c(1,2) lst1 - list(v1,v2) Of course there is the intuitive: as.data.frame(lst1) However, the recycling rule (expectedly) reclycles 1,2 versus using NAs as placeholders. Then, looking into Teetor's R Cookbook, there is a piece of code that looked (from the description) like it might do the trick: do.call(rbind, Map(as.data.frame,lst1) But I get the error: Error in match.names(clabs, names(xi)) : names do not match previous names Thinking the source of the error had to do with the vectors of unequal lenght, I tried Hadley's rbind.fill thusly: library(reshape) do.call(rbind.fill, Map(as.data.frame,lst1) Which produced a dataset, but gain, not in the desired format. Thanks in advance to anyone that can bring my frustrations to end! C [[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] turning a list of vectors into a data.frame (as rows of the DF)?
Most methods take the rows of data.frame()s to be very significant
(indicating multiple values from a single observation) so what you're
doing seems like it may be against the spirit of R, but if you want
a simple NA padding at the end, this should do it:
listToDF - function(inputList, fill = NA){
# Use fill = NULL for regular recycling behavior
maxLen = max(sapply(inputList, length))
for(i in seq_along(inputList))
inputList[[i]] - c(inputList[[i]], rep(fill, maxLen -
length(inputList[[i]])))
return(as.data.frame(inputList))
}
listToDF(list(x = 1:4, y = 1:2))
Michael
On Wed, Jan 11, 2012 at 2:40 PM, Chris Conner connerpha...@yahoo.com wrote:
As a newer R practicioner, it seems I stump myself weekly (at least) with
issues that have spinning my wheels. Here is yet another... I'm trying to
turn a list of numeric vectors (of uneual length) inot a dataframe. Each
vector held in the list represents a row, and there are some rows of unequal
length. I would like NAs as placeholders for missing data in the shorter
vectors. I think I'm missing something quite basic.
v1 - c(1,2,3,4)
v2 - c(1,2)
lst1 - list(v1,v2)
Of course there is the intuitive:
as.data.frame(lst1)
However, the recycling rule (expectedly) reclycles 1,2 versus using NAs as
placeholders.
Then, looking into Teetor's R Cookbook, there is a piece of code that looked
(from the description) like it might do the trick:
do.call(rbind, Map(as.data.frame,lst1)
But I get the error:
Error in match.names(clabs, names(xi)) :
names do not match previous names
Thinking the source of the error had to do with the vectors of unequal
lenght, I tried Hadley's rbind.fill thusly:
library(reshape)
do.call(rbind.fill, Map(as.data.frame,lst1)
Which produced a dataset, but gain, not in the desired format.
Thanks in advance to anyone that can bring my frustrations to end!
C
[[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.
__
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] turning a list of vectors into a data.frame (as rows of the DF)?
Perhaps the following does what you want. It extends
each element of your list to a common length, converts
that to a matrix, then to a data.frame:
f - function(data) {
nCol - max(vapply(data, length, 0))
data - lapply(data, function(row) c(row, rep(NA, nCol-length(row
data - matrix(unlist(data), nrow=length(data), ncol=nCol, byrow=TRUE)
data.frame(data)
}
E.g.,
rawData - list(c(1,2,3), c(11,12), integer(), 31)
f(rawData)
X1 X2 X3
1 1 2 3
2 11 12 NA
3 NA NA NA
4 31 NA NA
What sort of data is this? If it is longitudinal
it might be more straigtforward to store it as a
three-column data.frame (columns subject, time, value).
Bill Dunlap
Spotfire, TIBCO Software
wdunlap tibco.com
-Original Message-
From: r-help-boun...@r-project.org [mailto:r-help-boun...@r-project.org] On
Behalf Of Chris Conner
Sent: Wednesday, January 11, 2012 11:41 AM
To: HelpR
Subject: [R] turning a list of vectors into a data.frame (as rows of the DF)?
As a newer R practicioner, it seems I stump myself weekly (at least) with
issues that have spinning my
wheels. Here is yet another... I'm trying to turn a list of numeric vectors
(of uneual length) inot a
dataframe. Each vector held in the list represents a row, and there are some
rows of unequal
length. I would like NAs as placeholders for missing data in the shorter
vectors. I think I'm
missing something quite basic.
v1 - c(1,2,3,4)
v2 - c(1,2)
lst1 - list(v1,v2)
Of course there is the intuitive:
as.data.frame(lst1)
However, the recycling rule (expectedly) reclycles 1,2 versus using NAs as
placeholders.
Then, looking into Teetor's R Cookbook, there is a piece of code that looked
(from the description)
like it might do the trick:
do.call(rbind, Map(as.data.frame,lst1)
But I get the error:
Error in match.names(clabs, names(xi)) :
names do not match previous names
Thinking the source of the error had to do with the vectors of unequal
lenght, I tried Hadley's
rbind.fill thusly:
library(reshape)
do.call(rbind.fill, Map(as.data.frame,lst1)
Which produced a dataset, but gain, not in the desired format.
Thanks in advance to anyone that can bring my frustrations to end!
C
[[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] turning a list of vectors into a data.frame (as rows of the DF)?
On Jan 11, 2012, at 1:40 PM, Chris Conner wrote:
As a newer R practicioner, it seems I stump myself weekly (at least) with
issues that have spinning my wheels. Here is yet another... I'm trying to
turn a list of numeric vectors (of uneual length) inot a dataframe. Each
vector held in the list represents a row, and there are some rows of unequal
length. I would like NAs as placeholders for missing data in the shorter
vectors. I think I'm missing something quite basic.
v1 - c(1,2,3,4)
v2 - c(1,2)
lst1 - list(v1,v2)
Of course there is the intuitive:
as.data.frame(lst1)
However, the recycling rule (expectedly) reclycles 1,2 versus using NAs as
placeholders.
Then, looking into Teetor's R Cookbook, there is a piece of code that looked
(from the description) like it might do the trick:
do.call(rbind, Map(as.data.frame,lst1)
But I get the error:
Error in match.names(clabs, names(xi)) :
names do not match previous names
Thinking the source of the error had to do with the vectors of unequal
lenght, I tried Hadley's rbind.fill thusly:
library(reshape)
do.call(rbind.fill, Map(as.data.frame,lst1)
Which produced a dataset, but gain, not in the desired format.
Thanks in advance to anyone that can bring my frustrations to end!
C
[[alternative HTML version deleted]]
There may be an easier way, but try this:
list2df - function(x)
{
MAX.LEN - max(sapply(x, length), na.rm = TRUE)
DF - data.frame(lapply(x, function(x) c(x, rep(NA, MAX.LEN - length(x)
colnames(DF) - paste(V, seq(ncol(DF)), sep = )
DF
}
list2df(lst1)
V1 V2
1 1 1
2 2 2
3 3 NA
4 4 NA
HTH,
Marc Schwartz
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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.
