> ctr <- 1
> while(ctr <= 5){
+  print(paste("ctr is set to", ctr))
+  ctr <- ctr + 1  # Increment ctr
+ }

[1] "ctr is set to 1"
[1] "ctr is set to 2"
[1] "ctr is set to 3"
[1] "ctr is set to 4"
[1] "ctr is set to 5"

> # TEMPLATE for while loop
> while(condition){
+   expression
+ }

> cities <- c("Boone", "Charlotte", 
+             "Durham", "Raleigh")
> for(city in cities){
+   print(city)
+ }

[1] "Boone"
[1] "Charlotte"
[1] "Durham"
[1] "Raleigh"

> # for loop TEMPLATE
> for(var in seq){
+   expression
+ }

> cities <- list("Boone", "Charlotte", 
+             "Durham", "Raleigh")
> for(city in cities){
+   print(city)
+ }

[1] "Boone"
[1] "Charlotte"
[1] "Durham"
[1] "Raleigh"

> # for loop TEMPLATE
> for(var in seq){
+   expression
+ }

> cities <- list("Boone", "Charlotte", 
+             "Durham", "Raleigh")
> for(city in cities){
+   if(nchar(city) == 6){
+     break
+   }
+   print(city)
+ }

[1] "Boone"
[1] "Charlotte"

> # for loop TEMPLATE
> for(var in seq){
+   expression
+ }

> cities <- list("Boone", "Charlotte", 
+             "Durham", "Raleigh")
> for(city in cities){
+   if(nchar(city) == 6){
+     next  # Durham not printed
+   }
+   print(city)
+ }

[1] "Boone"
[1] "Charlotte"
[1] "Raleigh"

> # for loop TEMPLATE
> for(var in seq){
+   expression
+ }

> cities <- c("Boone", "Charlotte", 
+             "Durham", "Raleigh")
> for(i in 1:length(cities)){
+   print(cities[i])
+ }

[1] "Boone"
[1] "Charlotte"
[1] "Durham"
[1] "Raleigh"

> # for loop TEMPLATE
> for(var in seq){
+   expression
+ }

> cities <- c("Boone", "Charlotte", 
+             "Durham", "Raleigh")
> for(i in 1:length(cities)){
+   print(paste(cities[i], 
+         "is position", i , 
+         "in cities."))
+ }

[1] "Boone is position 1 in cities."
[1] "Charlotte is position 2 in cities."
[1] "Durham is position 3 in cities."
[1] "Raleigh is position 4 in cities."

> # for loop TEMPLATE
> for(var in seq){
+   expression
+ }