Damion Dooley
2009-Aug-19 19:12 UTC
[R] Basic question: Reading in multiple choice question responses to a single column in data frame
I'm using read.delim to successfully read in tab delimited data, but some
columns' values are comma seperated, reflecting the fact that user chose a
few answers on a multi-select question. I understand that each answer is
its own category and so could be represented as a seperate column in the
data set, but I'd like the option of reading in the data column, and
converting it to a vector that has all row values (comma seperated or not)
each have their own vector entry, so that the "table(columnData)"
function
does counts correctly.
So some code:
myData = read.delim(myDataFile, row.names=1,header=TRUE,skip=10); #works
fine
myColumn = myData[[question]]; #works fine, selects correct question
column data
myColumn data is now e.g.:
1
0
2
0,2
0
3
2
2,1
with the comma seperated values looking like atomic string values I guess.
But I would like:
1
0
2
0
2
0
3
2
2
1
I've tried various things, e.g. grep to recognize and expand the comma
seperated values, but since vector functions are at work, I can only replace
1 value back into the myColumn data, e.g. "0,2" entry becomes
"0" or "2" if
I use
myColumn=gsub("^([0-9]+),([0-9]+),$",c('\\1'),myColumn,perl=TRUE)
#or
replace with c('\\2')
but I can't replace into c('\\1','\\2')
Any elegant or otherwise ways to do this?
Much appreciated,
Damion
[[alternative HTML version deleted]]
Frank E Harrell Jr
2009-Aug-19 19:17 UTC
[R] Basic question: Reading in multiple choice question responses to a single column in data frame
You might look at the mChoice function in the Hmisc package for some indirect help. Frank Damion Dooley wrote:> I'm using read.delim to successfully read in tab delimited data, but some > columns' values are comma seperated, reflecting the fact that user chose a > few answers on a multi-select question. I understand that each answer is > its own category and so could be represented as a seperate column in the > data set, but I'd like the option of reading in the data column, and > converting it to a vector that has all row values (comma seperated or not) > each have their own vector entry, so that the "table(columnData)" function > does counts correctly. > > So some code: > > myData = read.delim(myDataFile, row.names=1,header=TRUE,skip=10); #works > fine > myColumn = myData[[question]]; #works fine, selects correct question > column data > > myColumn data is now e.g.: > > 1 > 0 > 2 > 0,2 > 0 > 3 > 2 > 2,1 > > with the comma seperated values looking like atomic string values I guess. > But I would like: > > 1 > 0 > 2 > 0 > 2 > 0 > 3 > 2 > 2 > 1 > > I've tried various things, e.g. grep to recognize and expand the comma > seperated values, but since vector functions are at work, I can only replace > 1 value back into the myColumn data, e.g. "0,2" entry becomes "0" or "2" if > I use > > myColumn=gsub("^([0-9]+),([0-9]+),$",c('\\1'),myColumn,perl=TRUE) #or > replace with c('\\2') > > but I can't replace into c('\\1','\\2') > > Any elegant or otherwise ways to do this? > > Much appreciated, > > Damion > > > > [[alternative HTML version deleted]] > > ______________________________________________ > R-help at 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. >-- Frank E Harrell Jr Professor and Chair School of Medicine Department of Biostatistics Vanderbilt University
Magnus Torfason
2009-Aug-19 19:32 UTC
[R] Basic question: Reading in multiple choice question responses to a single column in data frame
Are you looking for something like this?
> d =
data.frame(a=1:5,b=c("1","2,3","2","3,4","1"))
> d
a b
1 1 1
2 2 2,3
3 3 2
4 4 3,4
5 5 1
> multis = strsplit(d$b,",")
> counts = sapply(strsplit(d$b,","),length )
> d2 = data.frame( a=rep(d$a,counts), b=unlist(multis) )
> d2
a b
1 1 1
2 2 2
3 2 3
4 3 2
5 4 3
6 4 4
7 5 1
Best,
Magnus
On 8/19/2009 3:12 PM, Damion Dooley wrote:> I'm using read.delim to successfully read in tab delimited data, but
some
> columns' values are comma seperated, reflecting the fact that user
chose a
> few answers on a multi-select question. I understand that each answer is
> its own category and so could be represented as a seperate column in the
> data set, but I'd like the option of reading in the data column, and
> converting it to a vector that has all row values (comma seperated or not)
> each have their own vector entry, so that the "table(columnData)"
function
> does counts correctly.
>
> So some code:
>
> myData = read.delim(myDataFile, row.names=1,header=TRUE,skip=10);
#works
> fine
> myColumn = myData[[question]]; #works fine, selects correct question
> column data
>
> myColumn data is now e.g.:
>
> 1
> 0
> 2
> 0,2
> 0
> 3
> 2
> 2,1
>
> with the comma seperated values looking like atomic string values I guess.
> But I would like:
>
> 1
> 0
> 2
> 0
> 2
> 0
> 3
> 2
> 2
> 1
>
> I've tried various things, e.g. grep to recognize and expand the comma
> seperated values, but since vector functions are at work, I can only
replace
> 1 value back into the myColumn data, e.g. "0,2" entry becomes
"0" or "2" if
> I use
>
>
myColumn=gsub("^([0-9]+),([0-9]+),$",c('\\1'),myColumn,perl=TRUE)
#or
> replace with c('\\2')
>
> but I can't replace into c('\\1','\\2')
>
> Any elegant or otherwise ways to do this?
>
> Much appreciated,
>
> Damion
>
>
>
> [[alternative HTML version deleted]]
>
> ______________________________________________
> R-help at 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.
>
Damion Dooley
2009-Aug-19 20:07 UTC
[R] Basic question: Reading in multiple choice question responses to a single column in data frame
Magnus,
Looks like that solution should work, and I like the flexibility of your
data output, but I get a "error in strsplit(d$b,","):
non-character
argument" at:
multis = strsplit(d$b,",")
Seems like the c() function converts integer looking items like "1"
into
integers and then strsplit fails on them? I was running into this earlier
when attempting strsplit directly on column values.
Damion
-----Original Message-----
From: Magnus Torfason [mailto:zulutime.net at gmail.com]
Sent: August 19, 2009 12:33 PM
To: Damion Dooley
Cc: r-help at r-project.org
Subject: Re: [R] Basic question: Reading in multiple choice question
responses to a single column in data frame
Are you looking for something like this?
> d =
data.frame(a=1:5,b=c("1","2,3","2","3,4","1"))
> d
a b
1 1 1
2 2 2,3
3 3 2
4 4 3,4
5 5 1
> multis = strsplit(d$b,",")
> counts = sapply(strsplit(d$b,","),length )
> d2 = data.frame( a=rep(d$a,counts), b=unlist(multis) )
> d2
a b
1 1 1
2 2 2
3 2 3
4 3 2
5 4 3
6 4 4
7 5 1
Best,
Magnus
Damion Dooley
2009-Aug-20 03:06 UTC
[R] Basic question: Reading in multiple choice question responses to a single column in data frame
Slight addendum. Working from your code, I found 1 line of code does the
conversion:
myColumn = unlist(strsplit(as.character(myData[[myQuestion]]),","));
But the dataframe you set up may prove more useful.
Regards,
Damion
-----Original Message-----
From: Magnus Torfason [mailto:zulutime.net at gmail.com]
Sent: August 19, 2009 12:33 PM
To: Damion Dooley
Cc: r-help at r-project.org
Subject: Re: [R] Basic question: Reading in multiple choice question
responses to a single column in data frame
Are you looking for something like this?
> d =
data.frame(a=1:5,b=c("1","2,3","2","3,4","1"))
> d
a b
1 1 1
2 2 2,3
3 3 2
4 4 3,4
5 5 1
> multis = strsplit(d$b,",")
> counts = sapply(strsplit(d$b,","),length )
> d2 = data.frame( a=rep(d$a,counts), b=unlist(multis) )
> d2
a b
1 1 1
2 2 2
3 2 3
4 3 2
5 4 3
6 4 4
7 5 1
Best,
Magnus