How to get a .csv file into R?

Question

I have this .csv file:

ID,GRADES,GPA,Teacher,State

3,\"C\",2,\"Teacher3\",\"MA\"

1,\"A\",4,\"Teacher1\",\"California\"

And what I want to

Answer 1

You need read.csv("C:/somedirectory/some/file.csv") and in general it doesn't hurt to actually look at the help page including its example section at the bottom.

Answer 2

As Dirk said, the function you are after is 'read.csv' or one of the other read.table variants. Given your sample data above, I think you will want to do something like this:

setwd("c:/random/directory")

df <- read.csv("myRandomFile.csv", header=TRUE)

All we did in the above was set the directory to where your .csv file is and then read the .csv into a dataframe named df. You can check that the data loaded properly by checking the structure of the object with:

str(df)

Assuming the data loaded properly, you can think go on to perform any number of statistical methods with the data in your data frame. I think summary(df) would be a good place to start. Learning how to use the help in R will be immensely useful, and a quick read through the help on CRAN will save you lots of time in the future: http://cran.r-project.org/

Answer 3

You can use

df <- read.csv("filename.csv", header=TRUE)

# To loop each column
for (i in 1:ncol(df))
    {
    dosomething(df[,i])
    }
# To loop each row
for (i in 1:nrow(df))
    {
    dosomething(df[i,])
    }

Also, you may want to have a look to the apply function (type ?apply or help(apply))if you want to use the same function on each row/column

Answer 4

Since you say you want to access by position once your data is read in, you should know about R's subsetting/ indexing functions.

The easiest is

df[row,column]
#example
df[1:5,] #rows 1:5, all columns
df[,5] #all rows, column 5. 

Other methods are here. I personally use the dplyr package for intuitive data manipulation (not by position).

Answer 5

You mention that you will call on each vertical column so that you can perform calculations. I assume that you just want to examine each single variable. This can be done through the following.

df <- read.csv("myRandomFile.csv", header=TRUE)

df$ID

df$GRADES

df$GPA

Might be helpful just to assign the data to a variable.

var3 <- df$GPA

Answer 6

Please check this out if it helps you

df<-read.csv("F:/test.csv",header=FALSE,nrows=1) df V1 V2 V3 V4 V5 1 ID GRADES GPA Teacher State a<-c(df) a[1] $V1 [1] ID Levels: ID

a[2] $V2 [1] GRADES Levels: GRADES

a[3] $V3 [1] GPA Levels: GPA

a[4] $V4 [1] Teacher Levels: Teacher

a[5] $V5 [1] State Levels: State