amol- commented on a change in pull request #135:
URL: https://github.com/apache/arrow-cookbook/pull/135#discussion_r797532351
##########
File path: java/source/data.rst
##########
@@ -0,0 +1,360 @@
+=================
+Data manipulation
+=================
+
+Recipes related to compare, filtering or transforming data.
+
+.. contents::
+
+Compare Vectors for Field Equality
+==================================
+
+.. testcode::
+
+ import org.apache.arrow.vector.IntVector;
+ import org.apache.arrow.vector.compare.TypeEqualsVisitor;
+ import org.apache.arrow.memory.RootAllocator;
+
+ RootAllocator rootAllocator = new RootAllocator(Long.MAX_VALUE);
+ IntVector right = new IntVector("int", rootAllocator);
+ right.allocateNew(3);
+ right.set(0, 10);
+ right.set(1, 20);
+ right.set(2, 30);
+ right.setValueCount(3);
+ IntVector left1 = new IntVector("int", rootAllocator);
+ IntVector left2 = new IntVector("int2", rootAllocator);
+ TypeEqualsVisitor visitor = new TypeEqualsVisitor(right);
+
+ System.out.println(visitor.equals(left1));
+ System.out.println(visitor.equals(left2));
+
+.. testoutput::
+
+ true
+ false
+
+Compare Values on the Array
+===========================
+
+Comparing two values at the given indices in the vectors:
+
+.. testcode::
+
+ import org.apache.arrow.algorithm.sort.StableVectorComparator;
+ import org.apache.arrow.algorithm.sort.VectorValueComparator;
+ import org.apache.arrow.vector.VarCharVector;
+ import org.apache.arrow.memory.RootAllocator;
+
+ class TestVectorValueComparator extends
VectorValueComparator<VarCharVector> {
+ @Override
+ public int compareNotNull(int index1, int index2) {
+ byte b1 = vector1.get(index1)[0];
+ byte b2 = vector2.get(index2)[0];
+ return b1 - b2;
+ }
+
+ @Override
+ public VectorValueComparator<VarCharVector> createNew() {
+ return new TestVectorValueComparator();
+ }
+ }
+
+ RootAllocator rootAllocator = new RootAllocator(Long.MAX_VALUE);
+
+ VarCharVector vec = new VarCharVector("valueindexcomparator",
rootAllocator);
+ vec.allocateNew(3);
+ vec.setValueCount(3);
+ vec.set(0, "ba".getBytes());
+ vec.set(1, "abc".getBytes());
+ vec.set(2, "aa".getBytes());
+
+ VectorValueComparator<VarCharVector> comparatorValues = new
TestVectorValueComparator();
+ VectorValueComparator<VarCharVector> stableComparator = new
StableVectorComparator<>(comparatorValues);
+ stableComparator.attachVector(vec);
+
+ System.out.println(stableComparator.compare(0, 1) > 0);
+ System.out.println(stableComparator.compare(1, 2) < 0);
+
+.. testoutput::
+
+ true
+ true
+
+Search Values on the Array
+==========================
+
+Linear Search - O(n)
+********************
+
+Algorithm: org.apache.arrow.algorithm.search.VectorSearcher#linearSearch - O(n)
+
+.. testcode::
+
+ import org.apache.arrow.algorithm.search.VectorSearcher;
+ import org.apache.arrow.algorithm.sort.DefaultVectorComparators;
+ import org.apache.arrow.algorithm.sort.VectorValueComparator;
+ import org.apache.arrow.vector.IntVector;
+ import org.apache.arrow.memory.RootAllocator;
+
+ RootAllocator rootAllocator = new RootAllocator(Long.MAX_VALUE);
+ IntVector linearSearchVector = new IntVector("linearSearchVector",
rootAllocator);
+ linearSearchVector.allocateNew(10);
+ linearSearchVector.setValueCount(10);
+ for (int i = 0; i < 10; i++) {
+ linearSearchVector.set(i, i);
+ }
+ VectorValueComparator<IntVector> comparatorInt =
DefaultVectorComparators.createDefaultComparator(linearSearchVector);
+ List<Integer> listResultLinearSearch = new ArrayList<Integer>();
+ for (int i = 0; i < 10; i++) {
+ int result = VectorSearcher.linearSearch(linearSearchVector,
comparatorInt, linearSearchVector, i);
+ listResultLinearSearch.add(result);
+ }
Review comment:
I think that the for loop to search for all values makes things more
complicate to understand. Let's stick to how you search 1 value, it will make
the recipe easier to understand.
##########
File path: java/source/data.rst
##########
@@ -0,0 +1,360 @@
+=================
+Data manipulation
+=================
+
+Recipes related to compare, filtering or transforming data.
+
+.. contents::
+
+Compare Vectors for Field Equality
+==================================
+
+.. testcode::
+
+ import org.apache.arrow.vector.IntVector;
+ import org.apache.arrow.vector.compare.TypeEqualsVisitor;
+ import org.apache.arrow.memory.RootAllocator;
+
+ RootAllocator rootAllocator = new RootAllocator(Long.MAX_VALUE);
+ IntVector right = new IntVector("int", rootAllocator);
+ right.allocateNew(3);
+ right.set(0, 10);
+ right.set(1, 20);
+ right.set(2, 30);
+ right.setValueCount(3);
+ IntVector left1 = new IntVector("int", rootAllocator);
+ IntVector left2 = new IntVector("int2", rootAllocator);
+ TypeEqualsVisitor visitor = new TypeEqualsVisitor(right);
+
+ System.out.println(visitor.equals(left1));
+ System.out.println(visitor.equals(left2));
+
+.. testoutput::
+
+ true
+ false
+
+Compare Values on the Array
+===========================
+
+Comparing two values at the given indices in the vectors:
+
+.. testcode::
+
+ import org.apache.arrow.algorithm.sort.StableVectorComparator;
+ import org.apache.arrow.algorithm.sort.VectorValueComparator;
+ import org.apache.arrow.vector.VarCharVector;
+ import org.apache.arrow.memory.RootAllocator;
+
+ class TestVectorValueComparator extends
VectorValueComparator<VarCharVector> {
+ @Override
+ public int compareNotNull(int index1, int index2) {
+ byte b1 = vector1.get(index1)[0];
+ byte b2 = vector2.get(index2)[0];
+ return b1 - b2;
+ }
+
+ @Override
+ public VectorValueComparator<VarCharVector> createNew() {
+ return new TestVectorValueComparator();
+ }
+ }
+
+ RootAllocator rootAllocator = new RootAllocator(Long.MAX_VALUE);
+
+ VarCharVector vec = new VarCharVector("valueindexcomparator",
rootAllocator);
+ vec.allocateNew(3);
+ vec.setValueCount(3);
+ vec.set(0, "ba".getBytes());
+ vec.set(1, "abc".getBytes());
+ vec.set(2, "aa".getBytes());
+
+ VectorValueComparator<VarCharVector> comparatorValues = new
TestVectorValueComparator();
+ VectorValueComparator<VarCharVector> stableComparator = new
StableVectorComparator<>(comparatorValues);
+ stableComparator.attachVector(vec);
+
+ System.out.println(stableComparator.compare(0, 1) > 0);
+ System.out.println(stableComparator.compare(1, 2) < 0);
+
+.. testoutput::
+
+ true
+ true
+
+Search Values on the Array
+==========================
+
+Linear Search - O(n)
+********************
+
+Algorithm: org.apache.arrow.algorithm.search.VectorSearcher#linearSearch - O(n)
+
+.. testcode::
+
+ import org.apache.arrow.algorithm.search.VectorSearcher;
+ import org.apache.arrow.algorithm.sort.DefaultVectorComparators;
+ import org.apache.arrow.algorithm.sort.VectorValueComparator;
+ import org.apache.arrow.vector.IntVector;
+ import org.apache.arrow.memory.RootAllocator;
+
+ RootAllocator rootAllocator = new RootAllocator(Long.MAX_VALUE);
+ IntVector linearSearchVector = new IntVector("linearSearchVector",
rootAllocator);
+ linearSearchVector.allocateNew(10);
+ linearSearchVector.setValueCount(10);
+ for (int i = 0; i < 10; i++) {
+ linearSearchVector.set(i, i);
+ }
+ VectorValueComparator<IntVector> comparatorInt =
DefaultVectorComparators.createDefaultComparator(linearSearchVector);
+ List<Integer> listResultLinearSearch = new ArrayList<Integer>();
+ for (int i = 0; i < 10; i++) {
+ int result = VectorSearcher.linearSearch(linearSearchVector,
comparatorInt, linearSearchVector, i);
+ listResultLinearSearch.add(result);
+ }
+
+ System.out.println(listResultLinearSearch);
+
+.. testoutput::
+
+ [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
+
+Binary Search - O(log(n))
+*************************
+
+Algorithm: org.apache.arrow.algorithm.search.VectorSearcher#binarySearch -
O(log(n))
+
+.. testcode::
+
+ import org.apache.arrow.algorithm.search.VectorSearcher;
+ import org.apache.arrow.algorithm.sort.DefaultVectorComparators;
+ import org.apache.arrow.algorithm.sort.VectorValueComparator;
+ import org.apache.arrow.vector.IntVector;
+ import org.apache.arrow.memory.RootAllocator;
+
+ RootAllocator rootAllocator = new RootAllocator(Long.MAX_VALUE);
+ IntVector binarySearchVector = new IntVector("", rootAllocator);
+ binarySearchVector.allocateNew(10);
+ binarySearchVector.setValueCount(10);
+ for (int i = 0; i < 10; i++) {
+ binarySearchVector.set(i, i);
+ }
+ VectorValueComparator<IntVector> comparatorInt =
DefaultVectorComparators.createDefaultComparator(binarySearchVector);
+ List<Integer> listResultBinarySearch = new ArrayList<Integer>();
+ for (int i = 0; i < 10; i++) {
+ int result = VectorSearcher.binarySearch(binarySearchVector,
comparatorInt, binarySearchVector, i);
+ listResultBinarySearch.add(result);
+ }
Review comment:
I think that the for loop to search for all values makes things more
complicate to understand. Let's stick to how you search 1 value, it will make
the recipe easier to understand.
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