Lewis, Exercise 9

Exercise_9.R

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+# Exercise 9 
+
+#write a function to read data from file and calculate
+#coefficient of variation
+
+directoryVariation <- function(directory, column){
+  #set directory
+  setwd(directory)
+  #create a list of files from target directory
+  file_list <- list.files(path = ".", full.names = TRUE)
+  #create data frames for output
+  dataset <- data.frame()
+  final <- data.frame()
+  temp_data <- data.frame()
+  #read files and calculate variable
+  for (i in 1:length(file_list)){
+    temp_data <- read.csv(file_list[i], header = TRUE, stringsAsFactors = FALSE)
+    if (nrow(temp_data) > 50) {
+      dataset <- sd(temp_data$column) / mean(temp_data$column) * 100
+      #for each cycle of the loop, bind the new data to the building dataset
+      final <- rbind(dataset, final)
+    }
+    else if (nrow(temp_data) < 50) {
+      print ("Recommended 50 observations not reached for a file") 
+      input <- readline(prompt = "Override? (y/n): ")
+      if (input=="y"){
+        dataset <- sd(temp_data$column) / mean(temp_data$column) * 100
+        #for each cycle of the loop, bind the new data to the building dataset
+        final <- rbind(dataset, final)
+      } else {
+        dataset <- "N/A"
+        #for each cycle of the loop, bind the new data to the building dataset
+        final <- rbind(dataset, final)
+      }
+    }
+  }
+}