added isIn(array) method needed for work

lwhite1 · lwhite1 · commit 5e4457033c1c · 2016-08-26T07:54:11.000-04:00
diff --git a/src/main/java/com/github/lwhite1/tablesaw/api/CategoryColumn.java b/src/main/java/com/github/lwhite1/tablesaw/api/CategoryColumn.java
@@ -628,4 +628,24 @@ public int byteSize() {
   public byte[] asBytes(int rowNumber) {
     return ByteBuffer.allocate(4).putInt(getInt(rowNumber)).array();
   }
+
+  public Selection isIn(String ... strings) {
+    IntArrayList keys = new IntArrayList();
+    for (String string : strings) {
+      int key = lookupTable.get(string);
+      if (key >= 0) {
+        keys.add(key);
+      }
+    }
+
+    int i = 0;
+    Selection results = new BitmapBackedSelection();
+    for (int next : values) {
+      if (keys.contains(next)) {
+        results.add(i);
+      }
+      i++;
+    }
+    return results;
+  }
 }
diff --git a/src/main/java/com/github/lwhite1/tablesaw/filtering/text/TextIsIn.java b/src/main/java/com/github/lwhite1/tablesaw/filtering/text/TextIsIn.java
@@ -0,0 +1,31 @@
+package com.github.lwhite1.tablesaw.filtering.text;
+
+import com.github.lwhite1.tablesaw.api.CategoryColumn;
+import com.github.lwhite1.tablesaw.api.Table;
+import com.github.lwhite1.tablesaw.columns.Column;
+import com.github.lwhite1.tablesaw.columns.ColumnReference;
+import com.github.lwhite1.tablesaw.filtering.ColumnFilter;
+import com.github.lwhite1.tablesaw.util.Selection;
+
+import javax.annotation.concurrent.Immutable;
+
+/**
+ * A filtering that selects cells in which the string value is in the given array of strings
+ */
+@Immutable
+public class TextIsIn extends ColumnFilter {
+
+  private String[] strings;
+
+  public TextIsIn(ColumnReference reference, String ... strings) {
+    super(reference);
+    this.strings = strings;
+  }
+
+  @Override
+  public Selection apply(Table relation) {
+    Column column = relation.column(columnReference().getColumnName());
+    CategoryColumn textColumn = (CategoryColumn) column;
+    return textColumn.isIn(strings);
+  }
+}
diff --git a/src/test/java/com/github/lwhite1/tablesaw/api/CategoryColumnTest.java b/src/test/java/com/github/lwhite1/tablesaw/api/CategoryColumnTest.java
@@ -83,6 +83,15 @@ public void testStartsWith() {
     selection = categoryColumn.startsWith("T");
     assertEquals("Tennessee", categoryColumn.get(selection.get(0)));
     assertEquals("Texas", categoryColumn.get(selection.get(1)));
+  }
 
+  @Test
+  public void testIsIn() {
+    CategoryColumn categoryColumn = CategoryColumn.create("US States");
+    categoryColumn.addAll(TestDataUtil.usStates());
+    Selection selection = categoryColumn.isIn("Alabama", "Texas");
+    assertEquals("Alabama", categoryColumn.get(selection.get(0)));
+    assertEquals("Texas", categoryColumn.get(selection.get(1)));
+    assertEquals(2, selection.size());
   }
 }
