September 2017 Update

Task/Hash-join/Rust/hash-join.rust

@@ -12,13 +12,15 @@ fn main() {
     // hash phase
     let mut h = HashMap::new();
     for (i, a) in table_a.iter().enumerate() {
-        h.entry(a.1).or_insert(vec![]).push(i);
+        h.entry(a.1).or_insert_with(Vec::new).push(i);
     }
     // join phase
     for b in table_b {
-        for i in h.get(b.0).unwrap_or(&vec![]) {
-            let a = table_a.get(*i).unwrap();
-            println!("{:?} {:?}", a, b);
+        if let Some(vals) = h.get(b.0) {
+            for &val in vals {
+                let a = table_a.get(val).unwrap();
+                println!("{:?} {:?}", a, b);
+            }
         }
     }
 }