Using data.frame in R

Data frames in R

A useful feature of R is the data.frame.

What is a data.frame?

Without being an expert in R: a data.frame is like a table.  So when I read a table from a .csv file, then it read it into a data.frame.

mydata<-read.csv(“myfile.csv”, header=TRUE).

Reshape data with a data.frame on the fly

A very useful feature of a data.frame is that I can construct it, on the fly, so to speak.

Let’s say I make a list that could correspond to column, in ordinary English.

matrix(col1,10,1)

And now imagine that I concatenate ten letters into a row:

row1= c(“a”,”b”,”c”,”d”,”e”,”f”,”g”,”h”,”I”,”j”)

I can make data.frame of two columns with col1, as is, and row1 turned into a column.

data.frame(col1, row1)

This is a very handy piece of data reshaping and I can do this with any combination of numbers.

I can also make this a bit neater add headings to my columns by extending the command

data.frame(vname1 = col1, vname2 = row1)

If I need to return this from a function then of course I place the command in the line above where the x is: return(x)

If I need to put the data.frame into an object, then myobjectname<-data.frame(vname1 = col1, vname2 = row1)