Schmidt Exercise 9

Tutorial9.R

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+setwd("C:/Users/megan/Desktop/r-novice-inflammation/r-novice-inflammation-data/data")
+#list of files
+dir <- list.files("../data", full.names = TRUE)
+dir
+#return vector
+fileCOV <- c()
+#only csv files vector
+usable <- c()
+coeffientOfVariation <- function(dir){
+  #only csv files
+  usable <- dir[grep(".csv", dir)]
+  #for number of csv files
+  for (i in 1:length(usable)){
+    #read file
+    fil <- read.csv(file = usable[i], header = TRUE, stringsAsFactors = FALSE)
+    #column type
+    y <- sapply(fil,class)
+    #column names
+    z <- colnames(fil)
+    print(paste("Which column of the file would you like to calculate the coefficient of variation for? The columns are" , z , "/" ,y))
+    print("Please only select a column of integers or numerics.")
+    #input from user
+    x <- as.name(readline())
+    #test if the column has more than 50 entries
+    if (length(fil[[x]]) < 50){
+      print("An accurate coefficient of variation should have at least 50 entries, and this column has less than 50.")
+      question <- (readline("Would you like to continue? Yes or No: "))
+      #if less than 50 entries ask user if they want to continue
+      if (question == "Yes"){
+        #mean and removes NA occurrences
+        mean <- mean(fil[[x]], na.rm = TRUE)
+        #standard deviation and removes NA occurrences
+        std <- sd(fil[[x]], na.rm = TRUE)
+        #coefficient of variation
+        cov <- std/mean
+        #return vector
+        fileCOV <- c(fileCOV, cov)
+        i = i + 1
+      }else {
+        i = i +1
+      }
+    }
+    #if over 50 entries
+    else {
+      #mean and removes NA occurrences
+    mean <- mean(fil[[x]], na.rm = TRUE)
+    #standard deviation and removes NA occurrences
+    std <- sd(fil[[x]], na.rm = TRUE)
+    #coefficient of variation
+    cov <- std/mean
+    #return vector
+    fileCOV <- c(fileCOV, cov)
+    i = i + 1
+    }
+  }
+  #actual returning of vector
+  return(fileCOV)
+}
+coeffientOfVariation(dir)