Shaked iterator #9

JackSparrow4747 · 2023-12-20T14:02:52Z

No description provided.

guyeise5 · 2023-12-20T14:45:23Z

src/main/java/iterator/RichIterator.java

    }

    /**
     * @return the last element if not empty.
     */
    default Optional<A> lastOptional() {
-        throw new NotImplementedException();
+        if (!this.hasNext()) {


guyeise5 · 2023-12-20T14:51:31Z

src/main/java/iterator/RichIterator.java

+
+            return lastElement;
+        } catch (Exception exception) {
+            throw new NoSuchElementException();


Throwing new exception is redundant here because calling next on empty iterator throws NoSuchElementException.
Moreover it loses the data from the original exception. The exception should be called with something like:
new NoSuchElementExpcetion(exception)

guyeise5 · 2023-12-20T14:52:01Z

src/main/java/iterator/RichIterator.java

@@ -124,8 +172,24 @@ default boolean sameElements(Iterator<A> that) {
     * @return an iterator that contains only this element
     */
    static <A> RichIterator<A> pure(A elem) {
-        // TODO: implement this method
-        throw new NotImplementedException();
+        return new RichIterator<A>() {


guyeise5 · 2023-12-20T14:53:02Z

src/main/java/iterator/RichIterator.java

-        throw new NotImplementedException();
+        try {
+
+            return Collections.max(this.toList(), comparator);


This should be implemented without external libraries.

guyeise5 · 2023-12-20T14:53:26Z

src/main/java/iterator/RichIterator.java

+
+            return Collections.max(this.toList(), comparator);
+        } catch (Exception exception) {
+            throw new NoSuchElementException();


Same comment on the exception as before

guyeise5 · 2023-12-20T15:40:44Z

src/main/java/iterator/RichIterator.java

+        return new RichIterator<B>() {
+            @Override
+            public boolean hasNext() {
+                return RichIterator.this.hasNext();
+            }
+
+            @Override
+            public B next() {
+                return f.apply(RichIterator.this.next());
+            }
+        };


guyeise5 · 2023-12-20T15:42:16Z

src/main/java/iterator/RichIterator.java

@@ -236,7 +357,30 @@ default String mkString() {
     * RichIterator.apply(1,2,3,4).append(5) // 1,2,3,4,5
     */
    default RichIterator<A> append(A elem) {
-        throw new NotImplementedException();
+        return new RichIterator<A>() {


Can be reduced to
return appendAll(pure(elem))

guyeise5 · 2023-12-20T15:42:55Z

src/main/java/iterator/RichIterator.java

@@ -260,7 +424,29 @@ default RichIterator<A> appendAll(Iterator<A> elems) {
     * RichIterator.apply(1,2,3,4).prepend(0) // 0,1,2,3,4
     */
    default RichIterator<A> prepend(A elem) {
-        throw new NotImplementedException();


Can be reduced to
pure(elem).appendAll(this)

guyeise5 · 2023-12-20T15:43:17Z

src/main/java/iterator/RichIterator.java

@@ -272,7 +458,26 @@ default RichIterator<A> prepend(A elem) {
     * RichIterator.apply(4,5,6,7).prependAll(Arrays.asList(1,2,3)) // 1,2,3,4,5,6,7
     */
    default RichIterator<A> prependAll(Iterator<A> elems) {
-        throw new NotImplementedException();
+        return new RichIterator<A>() {


from(elems).appendAll(this)

guyeise5 · 2023-12-20T15:52:24Z

src/main/java/iterator/RichIterator.java

    default RichIterator<A> distinct() {
-        throw new NotImplementedException();
+        return new RichIterator<A>() {


Alternative solution

Set<A> visited = new HashSet<>(); return this.filter(x -> !visited.contains(x)).tapEach(visited::add);

JackSparrow4747 added 3 commits December 20, 2023 15:59

add .gitignore

13f6142

add iterator project

b222812

add iterator project

752e896

guyeise5 reviewed Dec 20, 2023

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guyeise5 closed this Feb 3, 2024

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Shaked iterator #9

Shaked iterator #9

JackSparrow4747 commented Dec 20, 2023

guyeise5 Dec 20, 2023

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Shaked iterator #9

Shaked iterator #9

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JackSparrow4747 commented Dec 20, 2023

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