CODEWITHSUNDEEP
rfunctioncsvcommand-line-arguments
Charlie
Charlie

Reputation: 15

Creating a read() command in a custom function

I'm still a rookie to the R world, in a very accelerated class with limited/no guidance. My assignment is to build a custom function that reads in a specific .csv, and take some specific columns out to be analyzed. Could anyone please offer some advice? The "sample code" I was given looks like this:

AnnualLekSurvey=function(data.in,stat.year){
d1=subset(data.in,year==stat.year)
d2=d1[c("year","complex","tot_male")]
      attach(d2)}

So when it's complete and I run it, I should be able to say:

AnnualLekSurvey(gsg_lek,2006)

where "gsg_lek" is the name of the file I want to import, and 2006 is the values from the "year" column that I want to subset. "complex" and "tot_male" will be the variable to be analyzed by "year", but I'm not worried about that code right now.

What I'm confused about is; how do I tell R that gsg_lek is a .csv file, and tell it to look in the proper directory for it when I run the custom function?

I saw one other vaguely similar example on here, and they had to use the if() and paste() commands to build the string of the file name - that seems like too much arbitrary work, unless I'm just being lazy...

Any help would be appreciated.

Upvotes: 0

Views: 404

Answers (1)

j1897
j1897

Reputation: 1557

You can make a function like this:

AnnualLekSurvey <- function(csvFile, stat.year)
{
  d1 <- read.csv(paste("C:/",csvFile,".csv", sep=""),header=T, sep=",")  
  d2 <- subset(d1, year==stat.year)
  d2 <- d2[, c("year","complex","tot_male")]
  return(d2)
}

The argument 'csvFile' in the function is the basename of your csv file. In this particular example, this has to be in your C:/ folder. If your file is in some other folder, you have to change the "C:/" in the function to the folder where your csv file is located.

Running the function:

data <- AnnualLekSurvey("gsg_lek", "2006")

Note that the arguments has to be within the quotes. 'data' will now contain the columns year, complex and tot_male of gsg_lek.csv corresponding to the year 2006

Upvotes: 1

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