Iterators

[learn-rust.git] / src / main.rs

diff --git a/src/main.rs b/src/main.rs
index 0ef1b16f4f9b19c7e9e1c71377abd4273acc0d1b..06d122b9c4c727f399d8273312ffcfb2a95088fd 100644 (file)
--- a/src/main.rs
+++ b/src/main.rs
@@ -65,7 +65,7 @@ fn test_hashmaps() {
     println!("scores after doubling: {:?}", scores);
 
     // double scores of immutable hashmap (rebuild it)
-    let collect_scores: HashMap<_, _> = collect_scores.iter()
+    let collect_scores: HashMap<_, _> = collect_scores.into_iter()
         .map(|(k, v)| (k, 2 * v))
         .collect();
     println!("collect_scores after rebuilding with doubling: {:?}", collect_scores);
@@ -157,6 +157,38 @@ fn test_closures() {
     println!("1st int call for value defg: {}", expensive_str_result.value("defg"));
 }
 
+fn test_iterators() {
+    let v1 = vec!["Hello", "good", "world"];
+    // implied default is .into_iter() which consumes v1
+    for s in v1.iter() {
+        println!("element: {}", s);
+    }
+    // can still use it now
+    println!("v1: {:?}", &v1);
+
+    // manual iteration
+    let mut v1_iter = v1.iter();
+    while let Some(e) = v1_iter.next() {
+        println!("while loop over iter: {}", e);
+    }
+
+    for l_element in v1.iter().filter(|x| x.contains('l')) {
+        println!("v1 element containing 'l': {}", l_element);
+    }
+
+    let v2 = vec![1, 2, 3];
+    let double_v2: Vec<_> = v2.iter().map(|x| x * 2).collect();
+    println!("doubled v2: {:?}", double_v2);
+
+    for i in v2.into_iter().map(|x| x * 3) {
+        println!("for loop triplicating v2: {}", i);
+    }
+
+    for i in Counter5::new() {
+        println!("Counter 5 value: {}", i);
+    }
+}
+
 fn main() {
     test_strings();
     test_vectors();
@@ -164,4 +196,5 @@ fn main() {
     test_files();
     test_generics();
     test_closures();
+    test_iterators();
 }