Combine list element by column name to make a dataframe

On 06 Apr 2015, at 08:05 , Mohammad Tanvir Ahamed via R-help <r-help at r-project.org> wrote:

Hi ,?

I have a example list like follow?


############################################

lst<-list(setNames(c(1,10,50,60,70,80),c("id","id1","math","phy","che","bio")),setNames(c(2,20,45),c("id","id1","phy")),setNames(c(3,30,75),c("id","id1","bio")))


My expected outcome :?

---------------------------------------------------------------------

df<-rbind(c(1,10,50,60,70,80),c(2,20,NA,45,NA,NA),c(3,30,NA,NA,NA,75))

colnames(df)<-c("id","id1","math","phy","che","bio")

row.names(df) <- NULL

df

############################################


Any suggestion will be appreciated .?

Hmm, in principle this looks like a merge() problem, if you first convert each list element to a data frame. That could be painful to get right though.

You could try something like this:

nm <- Reduce(union, lapply(lst, names)) # or just type it in
nm

[1] "id"   "id1"  "math" "phy"  "che"  "bio"

blank <- setNames(rep(NA_real_, length(nm)), nm)
fill1 <- function(x, blank) {blank[names(x)] <- x; blank}
lapply(lst, fill1, blank)

[[1]]
  id  id1 math  phy  che  bio 
   1   10   50   60   70   80 

[[2]]
  id  id1 math  phy  che  bio 
   2   20   NA   45   NA   NA 

[[3]]
  id  id1 math  phy  che  bio 
   3   30   NA   NA   NA   75

do.call(rbind,lapply(lst, fill1, blank))

id id1 math phy che bio
[1,]  1  10   50  60  70  80
[2,]  2  20   NA  45  NA  NA
[3,]  3  30   NA  NA  NA  75

(NB, this is a matrix, not a data frame, but so is your "df"!)

Notice that this does not do a proper merge on the id fields, i.e. if you have two different records with different grades (say one with "che" and another with "phy") on the same id, you get two records, not one. However, that might well be what you wanted.

(It is tempting to use

fill1 <- function(x) `[<-`(blank, names(x), x)
lapply(lst, fill1)

which does seem to work, but should probably be avoided because of the risk of destructive modification.)

Thanks in advance.

?

Best regards


...........................?

Tanvir Ahamed

G?teborg, Sweden




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Maybe something like the appended?

-- Mike

lst <- list(setNames(c(1,10,50,60,70,80),
                     c("id","id1","math","phy","che","bio")),
            setNames(c(2,20,45),
                     c("id","id1","phy")),
            setNames(c(3,30,75),
                     c("id","id1","bio")))

lst


df <- rbind(c(1,10,50,60,70,80),
            c(2,20,NA,45,NA,NA),
            c(3,30,NA,NA,NA,75))

colnames(df)<-c("id","id1","math","phy","che","bio")
row.names(df) <- NULL

df

allNames <- unique(unlist(lapply(lst, names)))
allNames

newLst <- lapply(lst, function(element) {
    element[allNames]
})
newLst

df2 <- do.call(rbind, newLst)
df2

all.equal(df, df2)

On Sun, Apr 5, 2015 at 11:05 PM, Mohammad Tanvir Ahamed via R-help

Hi ,

I have a example list like follow


############################################

lst<-list(setNames(c(1,10,50,60,70,80),c("id","id1","math","phy","che","bio")),setNames(c(2,20,45),c("id","id1","phy")),setNames(c(3,30,75),c("id","id1","bio")))


My expected outcome :

---------------------------------------------------------------------

df<-rbind(c(1,10,50,60,70,80),c(2,20,NA,45,NA,NA),c(3,30,NA,NA,NA,75))

colnames(df)<-c("id","id1","math","phy","che","bio")

row.names(df) <- NULL

df

############################################


Any suggestion will be appreciated .

Thanks in advance.



Best regards


...........................

Tanvir Ahamed

G?teborg, Sweden




        [[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.

forgot to cc to list

have a look at https://stat.ethz.ch/pipermail/r-help/2012-January/300275.html

and other messages in the sequence

if you use Marc Schwartz's list2df you with have to transpose  it with t()

Duncan

Duncan Mackay
Department of Agronomy and Soil Science
University of New England
Armidale NSW 2351
Email: home: mackay at northnet.com.au

-----Original Message-----
From: R-help [mailto:r-help-bounces at r-project.org] On Behalf Of Mohammad Tanvir Ahamed via R-help
Sent: Monday, 6 April 2015 16:06
To: r-help at r-project.org
Subject: [R] Combine list element by column name to make a dataframe

Hi ,?

I have a example list like follow?


############################################

lst<-list(setNames(c(1,10,50,60,70,80),c("id","id1","math","phy","che","bio")),setNames(c(2,20,45),c("id","id1","phy")),setNames(c(3,30,75),c("id","id1","bio")))


My expected outcome :?

---------------------------------------------------------------------

df<-rbind(c(1,10,50,60,70,80),c(2,20,NA,45,NA,NA),c(3,30,NA,NA,NA,75))

colnames(df)<-c("id","id1","math","phy","che","bio")

row.names(df) <- NULL

df

############################################


Any suggestion will be appreciated .?

Thanks in advance.

?

Best regards


...........................?

Tanvir Ahamed

G?teborg, Sweden