diff --git a/programming-with-r/assignments/assignment-1-air-pollution/complete.R b/programming-with-r/assignments/assignment-1-air-pollution/complete.R
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+++ b/programming-with-r/assignments/assignment-1-air-pollution/complete.R
@@ -0,0 +1,25 @@
+complete <- function(directory, id = 1:332) {
+  ## 'directory' is a character vector of length 1 indicating
+  ## the location of the CSV files
+  
+  ## 'id' is an integer vector indicating the monitor ID numbers
+  ## to be used
+  
+  ## Return a data frame of the form:
+  ## id nobs
+  ## 1  117
+  ## 2  1041
+  ## ...
+  ## where 'id' is the monitor ID number and 'nobs' is the
+  ## number of complete cases
+  allFiles <- list.files(path = directory, full.names = TRUE)
+  selectedData <- data.frame()
+  completeCases <- data.frame()
+  nobs <- data.frame();
+  for (i in id) { 
+    selectedData <- (read.csv(allFiles[i],header=TRUE))
+    nobs <- sum(complete.cases(selectedData))
+    completeCases <- rbind(completeCases, data.frame(i,nobs))
+  }
+  completeCases
+}
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