Hello R users, I have a set of data frames for which I am tallying row numbers, as shown below.> nrow(mC_Explant)[1] 14480> nrow(mC_Callus)[1] 23320> nrow(mC_RegenPlant)[1] 8108 etc. I want to create a new data frame which has the variable names as column headings, and then a single row with the nrow tallies. My first step was this: dfIntron <- c(nrow(mC_Explant), nrow(mC_Callus), nrow(mC_RegenPlant)) Then, to set the column names, I tried this, and got the following error: colnames(dfIntron) <- c("mC_Explant", "mC_Callus", "mC_RegenPlant") Error in `colnames<-`(`*tmp*`, value = c("mC_Explant", "mC_Callus", "mC_RegenPlant" : attempt to set colnames on object with less than two dimensions Even my first step seems wildly inefficient, and obviously doesn't work. There must be a simple way to do this, but I can't use table(), for example, as there are multiple data frames. Any help will be appreciated. --Kelly V.
Hi Kelly, c() creates a vector. You need data.frame() instead. dfIntron <- c(mC_Explant=nrow(mC_Explant), mC_Callus=nrow(mC_Callus), mC_RegenPlant=nrow(mC_RegenPlant)) # set colnames simultaneously. Sarah On Tue, Sep 20, 2011 at 2:23 PM, Vining, Kelly <Kelly.Vining at oregonstate.edu> wrote:> Hello R users, > I have a set of data frames for which I am tallying row numbers, as shown below. > >> nrow(mC_Explant) > [1] 14480 >> nrow(mC_Callus) > [1] 23320 >> nrow(mC_RegenPlant) > [1] 8108 > > etc. > > I want to create a new data frame which has the variable names as column headings, and then a single row with the nrow tallies. My first step was this: > > dfIntron <- c(nrow(mC_Explant), nrow(mC_Callus), nrow(mC_RegenPlant)) > > Then, to set the column names, I tried this, and got the following error: > > ?colnames(dfIntron) <- c("mC_Explant", "mC_Callus", "mC_RegenPlant") > Error in `colnames<-`(`*tmp*`, value = c("mC_Explant", "mC_Callus", "mC_RegenPlant" : > ?attempt to set colnames on object with less than two dimensions > > Even my first step seems wildly inefficient, and obviously doesn't work. There must be a simple way to do this, but I can't use table(), for example, as there are multiple data frames. > > Any help will be appreciated. > > --Kelly V. > >-- Sarah Goslee http://www.functionaldiversity.org
Hi:
Using Michael's example data, here's another approach:
x = data.frame(x = 1:5)
y = data.frame(y = 1:10)
z = data.frame(z = 1:3)
# Generate a vector to name the list components
nms <- c('x', 'y', 'z')
# Combine data frames into a list
L <- list(x, y, z)
# name them
names(L) <- nms
# Use lapply() to get the number of rows in each component data frame
as.data.frame(lapply(L, nrow))
x y z
1 5 10 3
HTH,
Dennis
On Tue, Sep 20, 2011 at 11:23 AM, Vining, Kelly
<Kelly.Vining at oregonstate.edu> wrote:> Hello R users,
> I have a set of data frames for which I am tallying row numbers, as shown
below.
>
>> nrow(mC_Explant)
> [1] 14480
>> nrow(mC_Callus)
> [1] 23320
>> nrow(mC_RegenPlant)
> [1] 8108
>
> etc.
>
> I want to create a new data frame which has the variable names as column
headings, and then a single row with the nrow tallies. My first step was this:
>
> dfIntron <- c(nrow(mC_Explant), nrow(mC_Callus), nrow(mC_RegenPlant))
>
> Then, to set the column names, I tried this, and got the following error:
>
> ?colnames(dfIntron) <- c("mC_Explant", "mC_Callus",
"mC_RegenPlant")
> Error in `colnames<-`(`*tmp*`, value = c("mC_Explant",
"mC_Callus", "mC_RegenPlant" :
> ?attempt to set colnames on object with less than two dimensions
>
> Even my first step seems wildly inefficient, and obviously doesn't
work. There must be a simple way to do this, but I can't use table(), for
example, as there are multiple data frames.
>
> Any help will be appreciated.
>
> --Kelly V.
>
>
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