Assignment-1-Part-1

Solution

.gitignore

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+**/.Rhistory
+**/.RHistory
+**/.RData
+**/.Rdata
+**/specdata/*

programming-with-r/assignments/assignment-1-air-pollution/pollutantmean.R

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+pollutantmean <- function(directory, pollutant, id = 1:332) {
+  ## 'directory' is a character vector of length 1 indicating
+  ## the location of the CSV files
+
+  ## 'pollutant' is a character vector of length 1 indicating
+  ## the name of the pollutant for which we will calculate the
+  ## mean; either "sulfate" or "nitrate".
+
+  ## 'id' is an integer vector indicating the monitor ID numbers
+  ## to be used
+
+  ## Return the mean of the pollutant across all monitors list
+  ## in the 'id' vector (ignoring NA values)
+
+  allFiles <- list.files(path = directory, full.names = TRUE)
+  selectedData <- data.frame()
+  for (i in id) {
+    selectedData <- rbind(selectedData, read.csv(allFiles[i]))
+  }
+  if (pollutant == 'sulfate') {
+    mean(selectedData$sulfate, na.rm = TRUE)
+  } else if (pollutant == 'nitrate') {
+    mean(selectedData$nitrate, na.rm = TRUE)
+  }
+
+}

samples/sample1.R

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+myfunction <- function() {
+  x <- rnorm(100)
+  mean(x)
+}
+
+second <- function(x) {
+  x + rnorm(length(x))
+}