This is a function I wrote in R to summarise the number of complete cases in any given table

complete.R

# R assignment 1 - Air Pollution

# preparation for R workspace

myTable <- NULL
mydata <- NULL
idd  <- NULL
nobs <- NULL


complete <- function(directory, id = 1:332) {
        ## 'directory' is a character vector of length 1 indicating the location of the CSV files
        ## 'id' is an integer vector indicating the monitor ID numbers
        
        ## Return a data frame of the form
        ## id nobs
        ## 1  117
        ## 2  1041
        
        ## set working dir
        
        setwd(paste("/Users/lucky1eva/Downloads/", directory, sep = '' ))
        
        ## transform the id into idd a vector of strings 
        for (i in 1:length(id)) {
                
                if (id[i] < 10) {
                        idd[i] <- paste("00", id[i], sep = '')
                        
                } else if (id[i] >= 10 && id[i] < 100) { 
                        idd[i] <- paste("0", id[i], sep = '')
                } else {
                        idd[i] <- id[i]
                }

        }
        
        ##  read CSV of selection and subset the table by complete cases function
        
        for (j in 1:length(idd)) {
                myTable <- read.csv(paste(idd[j], ".csv", sep = ''), header = TRUE)
                cc <- complete.cases(myTable)
                nobs[j] <- nrow(myTable[cc, ])
               
        }
        
        ## return the resulted numbers in id and nobs
        
        cbind(id, nobs)

}