Merge pull request #615 from mneumann/zip_all

Implement Zip::all()

Author: LukeMathWalker

src/zip/mod.rs

@@ -738,6 +738,32 @@ macro_rules! map_impl {
                 })
             }
 
+            /// Tests if every element of the iterator matches a predicate.
+            ///
+            /// Returns `true` if `predicate` evaluates to `true` for all elements.
+            /// Returns `true` if the input arrays are empty.
+            ///
+            /// Example:
+            ///
+            /// ```
+            /// use ndarray::{array, Zip};
+            /// let a = array![1, 2, 3];
+            /// let b = array![1, 4, 9];
+            /// assert!(Zip::from(&a).and(&b).all(|&a, &b| a * a == b));
+            /// ```
+            pub fn all<F>(mut self, mut predicate: F) -> bool
+                where F: FnMut($($p::Item),*) -> bool
+            {
+                self.apply_core(true, move |_, args| {
+                    let ($($p,)*) = args;
+                    if predicate($($p),*) {
+                        FoldWhile::Continue(true)
+                    } else {
+                        FoldWhile::Done(false)
+                    }
+                }).into_inner()
+            }
+
             expand_if!(@bool [$notlast]
 
             /// Include the producer `p` in the Zip.

tests/azip.rs

@@ -271,3 +271,22 @@ fn test_indices_split_1() {
         }
     }
 }
+
+#[test]
+fn test_zip_all() {
+    let a = Array::<f32, _>::zeros(62);
+    let b = Array::<f32, _>::ones(62);
+    let mut c = Array::<f32, _>::ones(62);
+    c[5] = 0.0;
+    assert_eq!(true, Zip::from(&a).and(&b).all(|&x, &y| x + y == 1.0));
+    assert_eq!(false, Zip::from(&a).and(&b).all(|&x, &y| x == y));
+    assert_eq!(false, Zip::from(&a).and(&c).all(|&x, &y| x + y == 1.0));
+}
+
+#[test]
+fn test_zip_all_empty_array() {
+    let a = Array::<f32, _>::zeros(0);
+    let b = Array::<f32, _>::ones(0);
+    assert_eq!(true, Zip::from(&a).and(&b).all(|&_x, &_y| true));
+    assert_eq!(true, Zip::from(&a).and(&b).all(|&_x, &_y| false));
+}