Adding V1

vsi.R

@@ -0,0 +1,91 @@
+library(foreign)
+library(dplyr)
+
+# Interviewer-Questionnaire with Inwer ID (intnum):
+dataset <- read.csv2("vsi.csv", dec=".", stringsAsFactors=F)
+
+extract_ap <- function (source) {
+  return (c(substr(source,0,7),
+           substr(source,16,23),
+           substr(source,32,39),
+           substr(source,48,55),
+           substr(source,64,71)));  
+}
+
+match_within <- function (t1,t2,t3) {
+  
+  matched_within = 0
+  
+  for (a in seq(1,5)) {
+    
+    if (t1[a] %in% t2 && t1[a] %in% t3) {
+      matched_within=matched_within + 1
+    }
+  }
+  if (matched_within >= 3) {
+    return (TRUE)
+  }
+  else {
+    return (FALSE)
+    
+  }
+  
+}
+
+match_outside <- function (a_t1, a_t2, a_t3, b_t1, b_t2, b_t3) {
+
+  matched = FALSE
+  
+  # only take cases that match !WITHIN!
+  if (match_within(a_t1, a_t2, a_t3) == FALSE || match_within(b_t1, b_t2, b_t3) == FALSE) {
+    return (FALSE) # no match, as we can't even do it within
+  }
+    
+  
+  matches=0
+  
+  # we iterate through all 5 APs. If at least three are repeated accross
+  # all time points in both surveys (a_t1... b_t3) we have a match
+  
+  for (a in seq(1,5)) {
+    
+    if (a_t1[a] %in% b_t1 && a_t1[a] %in% b_t2 && a_t1[a] %in% b_t3 &&
+        a_t2[a] %in% b_t1 && a_t2[a] %in% b_t2 && a_t2[a] %in% b_t3 &&
+        a_t3[a] %in% b_t1 && a_t3[a] %in% b_t2 && a_t3[a] %in% b_t3) 
+    {
+      matches=matches+1
+    }
+  }
+  
+  if (matches >= 3) {
+    return (TRUE)
+  }
+  else {
+    return (FALSE)
+  }
+}
+
+# non-optimal, case by case
+
+for(current_row in 1:nrow(dataset)) {
+  vsi_t1_exploded <- extract_ap(dataset[current_row,]$VSI1);
+  vsi_t2_exploded <- extract_ap(dataset[current_row,]$VSI2);
+  vsi_t3_exploded <- extract_ap(dataset[current_row,]$VSI3);
+  
+  # checking within
+  if (!match_within(vsi_t1_exploded,vsi_t2_exploded,vsi_t3_exploded)) {
+    print (paste("CASE ", current_row, " SEEM NOT TO BE TAKEN AT A SINGLE LOCATION!"))
+  }
+  
+  # compare against all other cases
+  for (compare_against in current_row+1:nrow(dataset)) {
+
+    t1_oth <- extract_ap(dataset[compare_against,]$VSI1);
+    t2_oth <- extract_ap(dataset[compare_against,]$VSI2);
+    t3_oth <- extract_ap(dataset[compare_against,]$VSI3);    
+
+    if (match_outside (vsi_t1_exploded, vsi_t2_exploded, vsi_t3_exploded, t1_oth, t2_oth, t3_oth)) {
+      print (paste ("WARNING, CASE ", current_row, " SEEMS TO BE TAKEN AT SAME LOCATION AS ", compare_against));
+    }
+  }
+}