如何格式化R data.frame输出？

Question

Let me start by saying I am brand new to R, so any solution with a detailed explanation would be appreciated so I can learn from it.

I have a set of csv files with the following rows of information:

"ID" "Date" "A" "B" (where A and B are some data points)

I am attempting to get the output in a meaningful manner and am stuck on what I am missing.

observations <- funtion(dir, id= 1:10){
  #get all file names in a vector
  all_files <- list.files(directory, full.names=TRUE)
  #get the subset of files we want to read
  file_contents <- lapply(all_files[id], read.csv)
  #cbind the file contents
  output <- do.call(rbind, file_contents)
  #remove all NA values
  output <- output[complete.cases(output), ]

  #at this point output is a data.frame so display the output
  table(output[["ID"]])
}

My current output is :

2    4    8   10  12
1000 500 200 150 100

which is correct but I need it in column form so it can be understood by looking at it. The output I am trying to get to is below:

   id obs_total
 1  2 1000
 2  4  500
 3  8  200
 4 10  150
 5 12  100

What am I missing here?

Answer 1

table outputs a contingency table. You want a data frame. You can wrap as.data.frame(...) around you output to convert it.

as.data.frame(table(ID = output[["ID"]]))

Answer 2

Assuming that the numbers are correct, looks like you have everything you need, just transpose the data frame. Try this:

mat<-matrix(round(runif(10),3),nrow=2)
df<-as.data.frame(mat)
colnames(df)=c("1","2","3","4","5")
t(df)