Exercise 9 Done

dirFunc.R

@@ -0,0 +1,54 @@
+# function call: array = dir(dirpath = full_path_to_directory, col = int, obs = bool)
+
+rm(list=ls())
+
+dir<-function(dirpath=".", col, obs=T){
+  # get a list of the files in the directory
+  files <- list.files(dirpath, pattern=".csv")
+
+  # Check input validity
+  # check that col is an integer
+  if(col != round(col)) {
+    print("Invalid col Value")
+    return ()
+  }
+  # check directory path
+    # user must input full path to directory
+  if(!file.exists(dirpath)) {
+    print("Invalid dirpath Value")
+    return ()
+  }
+
+  # initialize variables
+  setwd(file.path(dirpath))
+  result <- c()
+
+  # Loop through each file and calculate the coef dev
+  for (i in seq_along(files)) {
+    filetemp = read.csv(files[i], header=T, stringsAsFactors =F)
+    # check that col is valid
+    if (ncol(filetemp) < col) {
+      cat("Error with file", files[i], ": invalid col\n")
+      return()
+    }
+    # check if there are 50 observations
+    if (nrow(filetemp) < 50) {
+      if (obs){
+        # print error with number of observations and return null
+        cat("Error with file", files[i], ": not enough observations\n")
+        return ()
+      } else {
+        # if user overrides, just print a warning
+        cat("Warning: file", files[i], "has less that 50 observations\n")
+      }
+    }
+    # calculate coefdev and append to result
+    coefDev = sd(filetemp[,col], na.rm=T)/mean(filetemp[,col], na.rm=T)
+    result = c(result, coefDev)
+  }
+
+  # return result if eveything is successful
+  return (result)
+}
+
+print(dir(col=1))