R function that calculate correlation between two elements of a data frame if condition is meet -

so i've been trying make function work days..

function behaviour should follows:

1. go throw number of specified csv's = id
2. read.csv's , rbind them in 1 dataframe
3. remove rows have na values , keep complete ones. condition 1
4. then if sum of data[row_number,col_1] + data[row_number,col_2] > threshold, keep row, else row deleted.
5. finally correlate element-1 element-2 , return list of correlations done.

my code:

corr <- function(directory,threshold = 0,id = 1:332)   {    file.list <- list.files(directory, full.names = t)   dat <- data.frame()   for(i in id) {   dat <- rbind(dat,read.csv(file.list[i]))   }   complete_rows <- dat[complete.cases(dat),]   z <- data.frame()   z <- complete_rows[,2:3]   y <- data.frame()   y <- rowsums(z) > threshold   x <- data.frame()   x <- z[y,1:2]   for( in x[1:nrow(x),]){    cor(x[i,1],x[i,2], method = c("pearson"))    }       } 

my problem in step 5 correlating both elements , returning correlations..

thanks in advance.

try this:

   corr  <- function(directory, threshold = 0) {      files <- list.files(directory, full.names = t)      dat2 <- lapply(files, function(x) na.omit(read.csv(x)))      size <- unlist(lapply(dat2, nrow))      cors <- lapply(dat2[size > threshold], function(x) cor(x['nitrate'], x['sulfate']))      res <- unname(unlist(cors))     }