From b77a7a3a0957b337363471a5b8e870e7ae8d3227 Mon Sep 17 00:00:00 2001
From: MarkBaker <mark@lange.demon.co.uk>
Date: Thu, 11 Mar 2021 18:02:05 +0100
Subject: [PATCH 1/7] Extract LookupRef\INDEX() into index() method of
 LookupRef\Matrix class Additional tests

---
 samples/Calculations/LookupRef/ADDRESS.php    | 22 ++++++
 samples/Calculations/LookupRef/COLUMN.php     | 23 +++++++
 samples/Calculations/LookupRef/COLUMNS.php    | 21 ++++++
 samples/Calculations/LookupRef/INDEX.php      | 39 +++++++++++
 samples/Calculations/LookupRef/ROW.php        | 20 ++++++
 samples/Calculations/LookupRef/ROWS.php       | 20 ++++++
 src/PhpSpreadsheet/Calculation/LookupRef.php  | 52 ++------------
 .../Calculation/LookupRef/Matrix.php          | 68 +++++++++++++++++++
 .../LookupRef/RowColumnInformation.php        | 13 ++--
 tests/data/Calculation/LookupRef/INDEX.php    | 42 ++++++++++++
 tests/data/Calculation/LookupRef/ROW.php      |  7 ++
 11 files changed, 274 insertions(+), 53 deletions(-)
 create mode 100644 samples/Calculations/LookupRef/ADDRESS.php
 create mode 100644 samples/Calculations/LookupRef/COLUMN.php
 create mode 100644 samples/Calculations/LookupRef/COLUMNS.php
 create mode 100644 samples/Calculations/LookupRef/INDEX.php
 create mode 100644 samples/Calculations/LookupRef/ROW.php
 create mode 100644 samples/Calculations/LookupRef/ROWS.php

diff --git a/samples/Calculations/LookupRef/ADDRESS.php b/samples/Calculations/LookupRef/ADDRESS.php
new file mode 100644
index 0000000000..2377541d80
--- /dev/null
+++ b/samples/Calculations/LookupRef/ADDRESS.php
@@ -0,0 +1,22 @@
+<?php
+
+use PhpOffice\PhpSpreadsheet\Spreadsheet;
+
+require __DIR__ . '/../../Header.php';
+
+$helper->log('Returns a text reference to a single cell in a worksheet.');
+
+// Create new PhpSpreadsheet object
+$spreadsheet = new Spreadsheet();
+$worksheet = $spreadsheet->getActiveSheet();
+
+$worksheet->getCell('A1')->setValue('=ADDRESS(2,3)');
+$worksheet->getCell('A2')->setValue('=ADDRESS(2,3,2)');
+$worksheet->getCell('A3')->setValue('=ADDRESS(2,3,2,FALSE)');
+$worksheet->getCell('A4')->setValue('=ADDRESS(2,3,1,FALSE,"[Book1]Sheet1")');
+$worksheet->getCell('A5')->setValue('=ADDRESS(2,3,1,FALSE,"EXCEL SHEET")');
+
+for ($row = 1; $row <= 5; ++$row) {
+    $cell = $worksheet->getCell("A{$row}");
+    $helper->log("A{$row}: {$cell->getValue()} => {$cell->getCalculatedValue()}");
+}
diff --git a/samples/Calculations/LookupRef/COLUMN.php b/samples/Calculations/LookupRef/COLUMN.php
new file mode 100644
index 0000000000..e9e5846608
--- /dev/null
+++ b/samples/Calculations/LookupRef/COLUMN.php
@@ -0,0 +1,23 @@
+<?php
+
+use PhpOffice\PhpSpreadsheet\Spreadsheet;
+
+require __DIR__ . '/../../Header.php';
+
+$helper->log('Returns the column index of a cell.');
+
+// Create new PhpSpreadsheet object
+$spreadsheet = new Spreadsheet();
+$worksheet = $spreadsheet->getActiveSheet();
+
+$worksheet->getCell('A1')->setValue('=COLUMN(C13)');
+$worksheet->getCell('A2')->setValue('=COLUMN(E13:G15)');
+$worksheet->getCell('F1')->setValue('=COLUMN()');
+
+for ($row = 1; $row <= 2; ++$row) {
+    $cell = $worksheet->getCell("A{$row}");
+    $helper->log("A{$row}: {$cell->getValue()} => {$cell->getCalculatedValue()}");
+}
+
+$cell = $worksheet->getCell('F1');
+$helper->log("F1: {$cell->getValue()} => {$cell->getCalculatedValue()}");
diff --git a/samples/Calculations/LookupRef/COLUMNS.php b/samples/Calculations/LookupRef/COLUMNS.php
new file mode 100644
index 0000000000..4d7f8d10e6
--- /dev/null
+++ b/samples/Calculations/LookupRef/COLUMNS.php
@@ -0,0 +1,21 @@
+<?php
+
+use PhpOffice\PhpSpreadsheet\Spreadsheet;
+
+require __DIR__ . '/../../Header.php';
+
+$helper->log('Returns the number of columns in an array or reference.');
+
+// Create new PhpSpreadsheet object
+$spreadsheet = new Spreadsheet();
+$worksheet = $spreadsheet->getActiveSheet();
+
+$worksheet->getCell('A1')->setValue('=COLUMNS(C1:G4)');
+$worksheet->getCell('A2')->setValue('=COLUMNS({1,2,3;4,5,6})');
+$worksheet->getCell('A3')->setValue('=ROWS(C1:E4 D3:G5)');
+$worksheet->getCell('A4')->setValue('=COLUMNS(1:1)');
+
+for ($row = 1; $row <= 4; ++$row) {
+    $cell = $worksheet->getCell("A{$row}");
+    $helper->log("A{$row}: {$cell->getValue()} => {$cell->getCalculatedValue()}");
+}
diff --git a/samples/Calculations/LookupRef/INDEX.php b/samples/Calculations/LookupRef/INDEX.php
new file mode 100644
index 0000000000..2a483189dd
--- /dev/null
+++ b/samples/Calculations/LookupRef/INDEX.php
@@ -0,0 +1,39 @@
+<?php
+
+use PhpOffice\PhpSpreadsheet\Spreadsheet;
+
+require __DIR__ . '/../../Header.php';
+
+$helper->log('Returns the row index of a cell.');
+
+// Create new PhpSpreadsheet object
+$spreadsheet = new Spreadsheet();
+$worksheet = $spreadsheet->getActiveSheet();
+
+$data1 = [
+    ['Apples', 'Lemons'],
+    ['Bananas', 'Pears'],
+];
+
+$data2 = [
+    [4, 6],
+    [5, 3],
+    [6, 9],
+    [7, 5],
+    [8, 3],
+];
+
+$worksheet->fromArray($data1,null, 'A1');
+$worksheet->fromArray($data2,null, 'C1');
+
+$worksheet->getCell('A11')->setValue('=INDEX(A1:B2, 2, 2)');
+$worksheet->getCell('A12')->setValue('=INDEX(A1:B2, 2, 1)');
+$worksheet->getCell('A13')->setValue('=INDEX({1,2;3,4}, 0, 2)');
+$worksheet->getCell('A14')->setValue('=INDEX(C1:C5, 5)');
+$worksheet->getCell('A15')->setValue('=INDEX(C1:D5, 5, 2)');
+$worksheet->getCell('A16')->setValue('=SUM(INDEX(C1:D5, 5, 0))');
+
+for ($row = 11; $row <= 16; ++$row) {
+    $cell = $worksheet->getCell("A{$row}");
+    $helper->log("A{$row}: {$cell->getValue()} => {$cell->getCalculatedValue()}");
+}
diff --git a/samples/Calculations/LookupRef/ROW.php b/samples/Calculations/LookupRef/ROW.php
new file mode 100644
index 0000000000..560639a516
--- /dev/null
+++ b/samples/Calculations/LookupRef/ROW.php
@@ -0,0 +1,20 @@
+<?php
+
+use PhpOffice\PhpSpreadsheet\Spreadsheet;
+
+require __DIR__ . '/../../Header.php';
+
+$helper->log('Returns the row index of a cell.');
+
+// Create new PhpSpreadsheet object
+$spreadsheet = new Spreadsheet();
+$worksheet = $spreadsheet->getActiveSheet();
+
+$worksheet->getCell('A1')->setValue('=ROW(C13)');
+$worksheet->getCell('A2')->setValue('=ROW(E19:G21)');
+$worksheet->getCell('A3')->setValue('=ROW()');
+
+for ($row = 1; $row <= 3; ++$row) {
+    $cell = $worksheet->getCell("A{$row}");
+    $helper->log("A{$row}: {$cell->getValue()} => {$cell->getCalculatedValue()}");
+}
diff --git a/samples/Calculations/LookupRef/ROWS.php b/samples/Calculations/LookupRef/ROWS.php
new file mode 100644
index 0000000000..3cdf085bd9
--- /dev/null
+++ b/samples/Calculations/LookupRef/ROWS.php
@@ -0,0 +1,20 @@
+<?php
+
+use PhpOffice\PhpSpreadsheet\Spreadsheet;
+
+require __DIR__ . '/../../Header.php';
+
+$helper->log('Returns the row index of a cell.');
+
+// Create new PhpSpreadsheet object
+$spreadsheet = new Spreadsheet();
+$worksheet = $spreadsheet->getActiveSheet();
+
+$worksheet->getCell('A1')->setValue('=ROWS(C1:E4)');
+$worksheet->getCell('A2')->setValue('=ROWS({1,2,3;4,5,6})');
+$worksheet->getCell('A3')->setValue('=ROWS(C1:E4 D3:G5)');
+
+for ($row = 1; $row <= 3; ++$row) {
+    $cell = $worksheet->getCell("A{$row}");
+    $helper->log("A{$row}: {$cell->getValue()} => {$cell->getCalculatedValue()}");
+}
diff --git a/src/PhpSpreadsheet/Calculation/LookupRef.php b/src/PhpSpreadsheet/Calculation/LookupRef.php
index 39823a205d..8ae59d4669 100644
--- a/src/PhpSpreadsheet/Calculation/LookupRef.php
+++ b/src/PhpSpreadsheet/Calculation/LookupRef.php
@@ -529,59 +529,19 @@ public static function MATCH($lookupValue, $lookupArray, $matchType = 1)
      * Excel Function:
      *        =INDEX(range_array, row_num, [column_num])
      *
+     * @Deprecated 1.18.0
+     *
+     * @see Use the index() method in the LookupRef\Matrix class instead
+     *
      * @param mixed $arrayValues A range of cells or an array constant
      * @param mixed $rowNum The row in array from which to return a value. If row_num is omitted, column_num is required.
      * @param mixed $columnNum The column in array from which to return a value. If column_num is omitted, row_num is required.
      *
      * @return mixed the value of a specified cell or array of cells
      */
-    public static function INDEX($arrayValues, $rowNum = 0, $columnNum = 0)
+    public static function INDEX($matrix, $rowNum = 0, $columnNum = 0)
     {
-        $rowNum = Functions::flattenSingleValue($rowNum);
-        $columnNum = Functions::flattenSingleValue($columnNum);
-
-        if (($rowNum < 0) || ($columnNum < 0)) {
-            return Functions::VALUE();
-        }
-
-        if (!is_array($arrayValues) || ($rowNum > count($arrayValues))) {
-            return Functions::REF();
-        }
-
-        $rowKeys = array_keys($arrayValues);
-        $columnKeys = @array_keys($arrayValues[$rowKeys[0]]);
-
-        if ($columnNum > count($columnKeys)) {
-            return Functions::VALUE();
-        } elseif ($columnNum == 0) {
-            if ($rowNum == 0) {
-                return $arrayValues;
-            }
-            $rowNum = $rowKeys[--$rowNum];
-            $returnArray = [];
-            foreach ($arrayValues as $arrayColumn) {
-                if (is_array($arrayColumn)) {
-                    if (isset($arrayColumn[$rowNum])) {
-                        $returnArray[] = $arrayColumn[$rowNum];
-                    } else {
-                        return [$rowNum => $arrayValues[$rowNum]];
-                    }
-                } else {
-                    return $arrayValues[$rowNum];
-                }
-            }
-
-            return $returnArray;
-        }
-        $columnNum = $columnKeys[--$columnNum];
-        if ($rowNum > count($rowKeys)) {
-            return Functions::VALUE();
-        } elseif ($rowNum == 0) {
-            return $arrayValues[$columnNum];
-        }
-        $rowNum = $rowKeys[--$rowNum];
-
-        return $arrayValues[$rowNum][$columnNum];
+        return Matrix::index($matrix, $rowNum, $columnNum);
     }
 
     /**
diff --git a/src/PhpSpreadsheet/Calculation/LookupRef/Matrix.php b/src/PhpSpreadsheet/Calculation/LookupRef/Matrix.php
index 99fd6e6e74..567f9531e5 100644
--- a/src/PhpSpreadsheet/Calculation/LookupRef/Matrix.php
+++ b/src/PhpSpreadsheet/Calculation/LookupRef/Matrix.php
@@ -2,6 +2,8 @@
 
 namespace PhpOffice\PhpSpreadsheet\Calculation\LookupRef;
 
+use PhpOffice\PhpSpreadsheet\Calculation\Functions;
+
 class Matrix
 {
     /**
@@ -30,4 +32,70 @@ public static function transpose($matrixData)
 
         return $returnMatrix;
     }
+
+    /**
+     * INDEX.
+     *
+     * Uses an index to choose a value from a reference or array
+     *
+     * Excel Function:
+     *        =INDEX(range_array, row_num, [column_num])
+     *
+     * @param mixed $matrix A range of cells or an array constant
+     * @param mixed $rowNum The row in array from which to return a value.
+     *                          If row_num is omitted, column_num is required.
+     * @param mixed $columnNum The column in array from which to return a value.
+     *                          If column_num is omitted, row_num is required.
+     *
+     * @return mixed the value of a specified cell or array of cells
+     */
+    public static function index($matrix, $rowNum = 0, $columnNum = 0)
+    {
+        $rowNum = Functions::flattenSingleValue($rowNum);
+        $columnNum = Functions::flattenSingleValue($columnNum);
+
+        if (!is_numeric($rowNum) || !is_numeric($columnNum) ||( $rowNum < 0) || ($columnNum < 0)) {
+            return Functions::VALUE();
+        }
+
+        if (!is_array($matrix) || ($rowNum > count($matrix))) {
+            return Functions::REF();
+        }
+
+        $rowKeys = array_keys($matrix);
+        $columnKeys = @array_keys($matrix[$rowKeys[0]]);
+
+        if ($columnNum > count($columnKeys)) {
+            return Functions::VALUE();
+        } elseif ($columnNum == 0) {
+            if ($rowNum == 0) {
+                return $matrix;
+            }
+            $rowNum = $rowKeys[--$rowNum];
+            $returnArray = [];
+            foreach ($matrix as $arrayColumn) {
+                if (is_array($arrayColumn)) {
+                    if (isset($arrayColumn[$rowNum])) {
+                        $returnArray[] = $arrayColumn[$rowNum];
+                    } else {
+                        return [$rowNum => $matrix[$rowNum]];
+                    }
+                } else {
+                    return $matrix[$rowNum];
+                }
+            }
+
+            return $returnArray;
+        }
+
+        $columnNum = $columnKeys[--$columnNum];
+        if ($rowNum > count($rowKeys)) {
+            return Functions::VALUE();
+        } elseif ($rowNum == 0) {
+            return $matrix[$columnNum];
+        }
+        $rowNum = $rowKeys[--$rowNum];
+
+        return $matrix[$rowNum][$columnNum];
+    }
 }
diff --git a/src/PhpSpreadsheet/Calculation/LookupRef/RowColumnInformation.php b/src/PhpSpreadsheet/Calculation/LookupRef/RowColumnInformation.php
index 0cce806a5a..b0def78524 100644
--- a/src/PhpSpreadsheet/Calculation/LookupRef/RowColumnInformation.php
+++ b/src/PhpSpreadsheet/Calculation/LookupRef/RowColumnInformation.php
@@ -45,12 +45,11 @@ public static function COLUMN($cellAddress = null, ?Cell $cell = null)
                 [$startAddress, $endAddress] = explode(':', $cellAddress);
                 $startAddress = preg_replace('/[^a-z]/i', '', $startAddress);
                 $endAddress = preg_replace('/[^a-z]/i', '', $endAddress);
-                $returnValue = [];
-                do {
-                    $returnValue[] = (int) Coordinate::columnIndexFromString($startAddress);
-                } while ($startAddress++ != $endAddress);
 
-                return $returnValue;
+                return range(
+                    (int) Coordinate::columnIndexFromString($startAddress),
+                    (int) Coordinate::columnIndexFromString($endAddress)
+                );
             }
             $cellAddress = preg_replace('/[^a-z]/i', '', $cellAddress);
 
@@ -114,8 +113,8 @@ public static function ROW($cellAddress = null, ?Cell $pCell = null)
         }
 
         if (is_array($cellAddress)) {
-            foreach ($cellAddress as $columnKey => $rowValue) {
-                foreach ($rowValue as $rowKey => $cellValue) {
+            foreach ($cellAddress as $rowKey => $rowValue) {
+                foreach ($rowValue as $columnKey => $cellValue) {
                     return (int) preg_replace('/\D/', '', $rowKey);
                 }
             }
diff --git a/tests/data/Calculation/LookupRef/INDEX.php b/tests/data/Calculation/LookupRef/INDEX.php
index 55206270e0..e825774a54 100644
--- a/tests/data/Calculation/LookupRef/INDEX.php
+++ b/tests/data/Calculation/LookupRef/INDEX.php
@@ -87,4 +87,46 @@
             '21' => ['R' => 2],
         ],
     ],
+    [
+        'Pears',
+        [
+            ['Apples', 'Lemons'],
+            ['Bananas', 'Pears'],
+        ],
+        2,
+        2
+    ],
+    [
+        'Bananas',
+        [
+            ['Apples', 'Lemons'],
+            ['Bananas', 'Pears'],
+        ],
+        2,
+        1
+    ],
+    [
+        3,
+        [
+            [4, 6],
+            [5, 3],
+            [6, 9],
+            [7, 5],
+            [8, 3],
+        ],
+        5,
+        2
+    ],
+    [
+        [4 => [8, 3]],
+        [
+            [4, 6],
+            [5, 3],
+            [6, 9],
+            [7, 5],
+            [8, 3],
+        ],
+        5,
+        0
+    ],
 ];
diff --git a/tests/data/Calculation/LookupRef/ROW.php b/tests/data/Calculation/LookupRef/ROW.php
index 89566011ef..62545c7674 100644
--- a/tests/data/Calculation/LookupRef/ROW.php
+++ b/tests/data/Calculation/LookupRef/ROW.php
@@ -17,6 +17,13 @@
         [[10], [11], [12]],
         'C10:D12',
     ],
+    [
+        4,
+        [
+            4 => ['B' => 'B5', 'C' => 'C5', 'D' => 'D5'],
+            5 => ['B' => 'B5', 'C' => 'C5', 'D' => 'D5'],
+        ],
+    ],
     [
         [[10], [11], [12]],
         'Sheet1!C10:C12',

From f7f55f7a43c4f6dbe9cbe30143f555d45437231e Mon Sep 17 00:00:00 2001
From: MarkBaker <mark@lange.demon.co.uk>
Date: Thu, 11 Mar 2021 18:06:18 +0100
Subject: [PATCH 2/7] Cosmetics

---
 samples/Calculations/LookupRef/INDEX.php            | 4 ++--
 src/PhpSpreadsheet/Calculation/LookupRef.php        | 8 +++++---
 src/PhpSpreadsheet/Calculation/LookupRef/Matrix.php | 6 +++---
 tests/data/Calculation/LookupRef/INDEX.php          | 8 ++++----
 4 files changed, 14 insertions(+), 12 deletions(-)

diff --git a/samples/Calculations/LookupRef/INDEX.php b/samples/Calculations/LookupRef/INDEX.php
index 2a483189dd..9ef0b94562 100644
--- a/samples/Calculations/LookupRef/INDEX.php
+++ b/samples/Calculations/LookupRef/INDEX.php
@@ -23,8 +23,8 @@
     [8, 3],
 ];
 
-$worksheet->fromArray($data1,null, 'A1');
-$worksheet->fromArray($data2,null, 'C1');
+$worksheet->fromArray($data1, null, 'A1');
+$worksheet->fromArray($data2, null, 'C1');
 
 $worksheet->getCell('A11')->setValue('=INDEX(A1:B2, 2, 2)');
 $worksheet->getCell('A12')->setValue('=INDEX(A1:B2, 2, 1)');
diff --git a/src/PhpSpreadsheet/Calculation/LookupRef.php b/src/PhpSpreadsheet/Calculation/LookupRef.php
index 8ae59d4669..f1a147f18c 100644
--- a/src/PhpSpreadsheet/Calculation/LookupRef.php
+++ b/src/PhpSpreadsheet/Calculation/LookupRef.php
@@ -533,9 +533,11 @@ public static function MATCH($lookupValue, $lookupArray, $matchType = 1)
      *
      * @see Use the index() method in the LookupRef\Matrix class instead
      *
-     * @param mixed $arrayValues A range of cells or an array constant
-     * @param mixed $rowNum The row in array from which to return a value. If row_num is omitted, column_num is required.
-     * @param mixed $columnNum The column in array from which to return a value. If column_num is omitted, row_num is required.
+     * @param mixed $rowNum The row in the array or range from which to return a value.
+     *                          If row_num is omitted, column_num is required.
+     * @param mixed $columnNum The column in the array or range from which to return a value.
+     *                             If column_num is omitted, row_num is required.
+     * @param mixed $matrix
      *
      * @return mixed the value of a specified cell or array of cells
      */
diff --git a/src/PhpSpreadsheet/Calculation/LookupRef/Matrix.php b/src/PhpSpreadsheet/Calculation/LookupRef/Matrix.php
index 567f9531e5..6719af25c4 100644
--- a/src/PhpSpreadsheet/Calculation/LookupRef/Matrix.php
+++ b/src/PhpSpreadsheet/Calculation/LookupRef/Matrix.php
@@ -42,9 +42,9 @@ public static function transpose($matrixData)
      *        =INDEX(range_array, row_num, [column_num])
      *
      * @param mixed $matrix A range of cells or an array constant
-     * @param mixed $rowNum The row in array from which to return a value.
+     * @param mixed $rowNum The row in the array or range from which to return a value.
      *                          If row_num is omitted, column_num is required.
-     * @param mixed $columnNum The column in array from which to return a value.
+     * @param mixed $columnNum The column in the array or range from which to return a value.
      *                          If column_num is omitted, row_num is required.
      *
      * @return mixed the value of a specified cell or array of cells
@@ -54,7 +54,7 @@ public static function index($matrix, $rowNum = 0, $columnNum = 0)
         $rowNum = Functions::flattenSingleValue($rowNum);
         $columnNum = Functions::flattenSingleValue($columnNum);
 
-        if (!is_numeric($rowNum) || !is_numeric($columnNum) ||( $rowNum < 0) || ($columnNum < 0)) {
+        if (!is_numeric($rowNum) || !is_numeric($columnNum) || ($rowNum < 0) || ($columnNum < 0)) {
             return Functions::VALUE();
         }
 
diff --git a/tests/data/Calculation/LookupRef/INDEX.php b/tests/data/Calculation/LookupRef/INDEX.php
index e825774a54..342fb00f72 100644
--- a/tests/data/Calculation/LookupRef/INDEX.php
+++ b/tests/data/Calculation/LookupRef/INDEX.php
@@ -94,7 +94,7 @@
             ['Bananas', 'Pears'],
         ],
         2,
-        2
+        2,
     ],
     [
         'Bananas',
@@ -103,7 +103,7 @@
             ['Bananas', 'Pears'],
         ],
         2,
-        1
+        1,
     ],
     [
         3,
@@ -115,7 +115,7 @@
             [8, 3],
         ],
         5,
-        2
+        2,
     ],
     [
         [4 => [8, 3]],
@@ -127,6 +127,6 @@
             [8, 3],
         ],
         5,
-        0
+        0,
     ],
 ];

From 42b0a543c9f06a47752b7941d49dc3b3754f0436 Mon Sep 17 00:00:00 2001
From: MarkBaker <mark@lange.demon.co.uk>
Date: Thu, 11 Mar 2021 20:17:03 +0100
Subject: [PATCH 3/7] Bugfix for returning a column using INDEX()

---
 .../Calculation/LookupRef/Matrix.php          |  9 ++++--
 .../Functions/LookupRef/IndexTest.php         |  1 +
 tests/data/Calculation/LookupRef/INDEX.php    | 30 ++++++++++++++++++-
 3 files changed, 37 insertions(+), 3 deletions(-)

diff --git a/src/PhpSpreadsheet/Calculation/LookupRef/Matrix.php b/src/PhpSpreadsheet/Calculation/LookupRef/Matrix.php
index 6719af25c4..7e69451879 100644
--- a/src/PhpSpreadsheet/Calculation/LookupRef/Matrix.php
+++ b/src/PhpSpreadsheet/Calculation/LookupRef/Matrix.php
@@ -66,7 +66,7 @@ public static function index($matrix, $rowNum = 0, $columnNum = 0)
         $columnKeys = @array_keys($matrix[$rowKeys[0]]);
 
         if ($columnNum > count($columnKeys)) {
-            return Functions::VALUE();
+            return Functions::REF();
         } elseif ($columnNum == 0) {
             if ($rowNum == 0) {
                 return $matrix;
@@ -92,7 +92,12 @@ public static function index($matrix, $rowNum = 0, $columnNum = 0)
         if ($rowNum > count($rowKeys)) {
             return Functions::VALUE();
         } elseif ($rowNum == 0) {
-            return $matrix[$columnNum];
+            return array_map(
+                function ($value) {
+                    return [$value];
+                },
+                array_column($matrix, $columnNum)
+            );
         }
         $rowNum = $rowKeys[--$rowNum];
 
diff --git a/tests/PhpSpreadsheetTests/Calculation/Functions/LookupRef/IndexTest.php b/tests/PhpSpreadsheetTests/Calculation/Functions/LookupRef/IndexTest.php
index 8ff6693169..c84a504de2 100644
--- a/tests/PhpSpreadsheetTests/Calculation/Functions/LookupRef/IndexTest.php
+++ b/tests/PhpSpreadsheetTests/Calculation/Functions/LookupRef/IndexTest.php
@@ -21,6 +21,7 @@ protected function setUp(): void
     public function testINDEX($expectedResult, ...$args): void
     {
         $result = LookupRef::INDEX(...$args);
+//        var_dump($result);
         self::assertEquals($expectedResult, $result);
     }
 
diff --git a/tests/data/Calculation/LookupRef/INDEX.php b/tests/data/Calculation/LookupRef/INDEX.php
index 342fb00f72..157794ab18 100644
--- a/tests/data/Calculation/LookupRef/INDEX.php
+++ b/tests/data/Calculation/LookupRef/INDEX.php
@@ -54,7 +54,7 @@
         -1,
     ],
     [
-        '#VALUE!', // Expected
+        '#REF!', // Expected
         // Input
         [
             '20' => ['R' => 1, 'S' => 3],
@@ -63,6 +63,16 @@
         2,
         10,
     ],
+    [
+        '#REF!', // Expected
+        // Input
+        [
+            '20' => ['R' => 1, 'S' => 3],
+            '21' => ['R' => 2, 'S' => 4],
+        ],
+        10,
+        2,
+    ],
     [
         4, // Expected
         // Input
@@ -129,4 +139,22 @@
         5,
         0,
     ],
+    [
+        [
+            [6],
+            [3],
+            [9],
+            [5],
+            [3],
+        ],
+        [
+            [4, 6],
+            [5, 3],
+            [6, 9],
+            [7, 5],
+            [8, 3],
+        ],
+        0,
+        2,
+    ],
 ];

From b451846dcaaccf5d73069d72be6be37d8e0946b7 Mon Sep 17 00:00:00 2001
From: MarkBaker <mark@lange.demon.co.uk>
Date: Thu, 11 Mar 2021 20:55:58 +0100
Subject: [PATCH 4/7] Some improvements to ROW() and COLUMN()

---
 .../Calculation/LookupRef/Matrix.php          |  8 +--
 .../LookupRef/RowColumnInformation.php        | 59 ++++++++++---------
 2 files changed, 34 insertions(+), 33 deletions(-)

diff --git a/src/PhpSpreadsheet/Calculation/LookupRef/Matrix.php b/src/PhpSpreadsheet/Calculation/LookupRef/Matrix.php
index 7e69451879..decc5b401b 100644
--- a/src/PhpSpreadsheet/Calculation/LookupRef/Matrix.php
+++ b/src/PhpSpreadsheet/Calculation/LookupRef/Matrix.php
@@ -67,7 +67,9 @@ public static function index($matrix, $rowNum = 0, $columnNum = 0)
 
         if ($columnNum > count($columnKeys)) {
             return Functions::REF();
-        } elseif ($columnNum == 0) {
+        }
+
+        if ($columnNum == 0) {
             if ($rowNum == 0) {
                 return $matrix;
             }
@@ -89,9 +91,7 @@ public static function index($matrix, $rowNum = 0, $columnNum = 0)
         }
 
         $columnNum = $columnKeys[--$columnNum];
-        if ($rowNum > count($rowKeys)) {
-            return Functions::VALUE();
-        } elseif ($rowNum == 0) {
+        if ($rowNum == 0) {
             return array_map(
                 function ($value) {
                     return [$value];
diff --git a/src/PhpSpreadsheet/Calculation/LookupRef/RowColumnInformation.php b/src/PhpSpreadsheet/Calculation/LookupRef/RowColumnInformation.php
index b0def78524..32977b8c7e 100644
--- a/src/PhpSpreadsheet/Calculation/LookupRef/RowColumnInformation.php
+++ b/src/PhpSpreadsheet/Calculation/LookupRef/RowColumnInformation.php
@@ -39,22 +39,23 @@ public static function COLUMN($cellAddress = null, ?Cell $cell = null)
 
                 return (int) Coordinate::columnIndexFromString($columnKey);
             }
-        } else {
-            [, $cellAddress] = Worksheet::extractSheetTitle($cellAddress, true);
-            if (strpos($cellAddress, ':') !== false) {
-                [$startAddress, $endAddress] = explode(':', $cellAddress);
-                $startAddress = preg_replace('/[^a-z]/i', '', $startAddress);
-                $endAddress = preg_replace('/[^a-z]/i', '', $endAddress);
-
-                return range(
-                    (int) Coordinate::columnIndexFromString($startAddress),
-                    (int) Coordinate::columnIndexFromString($endAddress)
-                );
-            }
-            $cellAddress = preg_replace('/[^a-z]/i', '', $cellAddress);
+        }
 
-            return (int) Coordinate::columnIndexFromString($cellAddress);
+        [, $cellAddress] = Worksheet::extractSheetTitle($cellAddress, true);
+        if (strpos($cellAddress, ':') !== false) {
+            [$startAddress, $endAddress] = explode(':', $cellAddress);
+            $startAddress = preg_replace('/[^a-z]/i', '', $startAddress);
+            $endAddress = preg_replace('/[^a-z]/i', '', $endAddress);
+
+            return range(
+                (int) Coordinate::columnIndexFromString($startAddress),
+                (int) Coordinate::columnIndexFromString($endAddress)
+            );
         }
+
+        $cellAddress = preg_replace('/[^a-z]/i', '', $cellAddress);
+
+        return (int) Coordinate::columnIndexFromString($cellAddress);
     }
 
     /**
@@ -118,23 +119,23 @@ public static function ROW($cellAddress = null, ?Cell $pCell = null)
                     return (int) preg_replace('/\D/', '', $rowKey);
                 }
             }
-        } else {
-            [, $cellAddress] = Worksheet::extractSheetTitle($cellAddress, true);
-            if (strpos($cellAddress, ':') !== false) {
-                [$startAddress, $endAddress] = explode(':', $cellAddress);
-                $startAddress = preg_replace('/\D/', '', $startAddress);
-                $endAddress = preg_replace('/\D/', '', $endAddress);
-                $returnValue = [];
-                do {
-                    $returnValue[][] = (int) $startAddress;
-                } while ($startAddress++ != $endAddress);
-
-                return $returnValue;
-            }
-            [$cellAddress] = explode(':', $cellAddress);
+        }
 
-            return (int) preg_replace('/\D/', '', $cellAddress);
+        [, $cellAddress] = Worksheet::extractSheetTitle($cellAddress, true);
+        if (strpos($cellAddress, ':') !== false) {
+            [$startAddress, $endAddress] = explode(':', $cellAddress);
+            $startAddress = preg_replace('/\D/', '', $startAddress);
+            $endAddress = preg_replace('/\D/', '', $endAddress);
+            $returnValue = [];
+            do {
+                $returnValue[][] = (int) $startAddress;
+            } while ($startAddress++ != $endAddress);
+
+            return $returnValue;
         }
+        [$cellAddress] = explode(':', $cellAddress);
+
+        return (int) preg_replace('/\D/', '', $cellAddress);
     }
 
     /**

From 3bbbd1bd0a4addf5a084cbbd6d1c5c36f09a31e6 Mon Sep 17 00:00:00 2001
From: MarkBaker <mark@lange.demon.co.uk>
Date: Thu, 11 Mar 2021 21:30:43 +0100
Subject: [PATCH 5/7] Simplify some of the INDEX() logic, eliminating redundant
 code

---
 .../Calculation/LookupRef/Matrix.php            | 17 +++++------------
 .../LookupRef/RowColumnInformation.php          |  4 ++--
 2 files changed, 7 insertions(+), 14 deletions(-)

diff --git a/src/PhpSpreadsheet/Calculation/LookupRef/Matrix.php b/src/PhpSpreadsheet/Calculation/LookupRef/Matrix.php
index decc5b401b..bf06814485 100644
--- a/src/PhpSpreadsheet/Calculation/LookupRef/Matrix.php
+++ b/src/PhpSpreadsheet/Calculation/LookupRef/Matrix.php
@@ -73,21 +73,14 @@ public static function index($matrix, $rowNum = 0, $columnNum = 0)
             if ($rowNum == 0) {
                 return $matrix;
             }
+
             $rowNum = $rowKeys[--$rowNum];
-            $returnArray = [];
-            foreach ($matrix as $arrayColumn) {
-                if (is_array($arrayColumn)) {
-                    if (isset($arrayColumn[$rowNum])) {
-                        $returnArray[] = $arrayColumn[$rowNum];
-                    } else {
-                        return [$rowNum => $matrix[$rowNum]];
-                    }
-                } else {
-                    return $matrix[$rowNum];
-                }
+            $row = $matrix[$rowNum];
+            if (is_array($row)) {
+                return [$rowNum => $row];
             }
 
-            return $returnArray;
+            return $row;
         }
 
         $columnNum = $columnKeys[--$columnNum];
diff --git a/src/PhpSpreadsheet/Calculation/LookupRef/RowColumnInformation.php b/src/PhpSpreadsheet/Calculation/LookupRef/RowColumnInformation.php
index 32977b8c7e..c78e65db56 100644
--- a/src/PhpSpreadsheet/Calculation/LookupRef/RowColumnInformation.php
+++ b/src/PhpSpreadsheet/Calculation/LookupRef/RowColumnInformation.php
@@ -73,7 +73,7 @@ public static function COLUMN($cellAddress = null, ?Cell $cell = null)
      */
     public static function COLUMNS($cellAddress = null)
     {
-        if ($cellAddress === null || $cellAddress === '') {
+        if ($cellAddress === null || (is_string($cellAddress) && trim($cellAddress) === '')) {
             return 1;
         } elseif (!is_array($cellAddress)) {
             return Functions::VALUE();
@@ -153,7 +153,7 @@ public static function ROW($cellAddress = null, ?Cell $pCell = null)
      */
     public static function ROWS($cellAddress = null)
     {
-        if ($cellAddress === null || $cellAddress === '') {
+        if ($cellAddress === null || (is_string($cellAddress) && trim($cellAddress) === '')) {
             return 1;
         } elseif (!is_array($cellAddress)) {
             return Functions::VALUE();

From 36211c27675757238eabedda41570619f50f45a1 Mon Sep 17 00:00:00 2001
From: MarkBaker <mark@lange.demon.co.uk>
Date: Thu, 11 Mar 2021 21:57:31 +0100
Subject: [PATCH 6/7] Some refactoring

---
 .../Calculation/LookupRef/Matrix.php          | 27 +++++++++++--------
 1 file changed, 16 insertions(+), 11 deletions(-)

diff --git a/src/PhpSpreadsheet/Calculation/LookupRef/Matrix.php b/src/PhpSpreadsheet/Calculation/LookupRef/Matrix.php
index bf06814485..8859a28757 100644
--- a/src/PhpSpreadsheet/Calculation/LookupRef/Matrix.php
+++ b/src/PhpSpreadsheet/Calculation/LookupRef/Matrix.php
@@ -70,17 +70,7 @@ public static function index($matrix, $rowNum = 0, $columnNum = 0)
         }
 
         if ($columnNum == 0) {
-            if ($rowNum == 0) {
-                return $matrix;
-            }
-
-            $rowNum = $rowKeys[--$rowNum];
-            $row = $matrix[$rowNum];
-            if (is_array($row)) {
-                return [$rowNum => $row];
-            }
-
-            return $row;
+            return self::extractRowValue($matrix, $rowKeys, $rowNum);
         }
 
         $columnNum = $columnKeys[--$columnNum];
@@ -96,4 +86,19 @@ function ($value) {
 
         return $matrix[$rowNum][$columnNum];
     }
+
+    private static function extractRowValue(array $matrix, array $rowKeys, int $rowNum)
+    {
+        if ($rowNum == 0) {
+            return $matrix;
+        }
+
+        $rowNum = $rowKeys[--$rowNum];
+        $row = $matrix[$rowNum];
+        if (is_array($row)) {
+            return [$rowNum => $row];
+        }
+
+        return $row;
+    }
 }

From 7714a033c99893f8d26fff3839fea09eaefa1fdc Mon Sep 17 00:00:00 2001
From: MarkBaker <mark@lange.demon.co.uk>
Date: Thu, 11 Mar 2021 22:16:30 +0100
Subject: [PATCH 7/7] Some refactoring

---
 .../LookupRef/RowColumnInformation.php            | 15 ++++++++-------
 1 file changed, 8 insertions(+), 7 deletions(-)

diff --git a/src/PhpSpreadsheet/Calculation/LookupRef/RowColumnInformation.php b/src/PhpSpreadsheet/Calculation/LookupRef/RowColumnInformation.php
index c78e65db56..19d0d5ff8a 100644
--- a/src/PhpSpreadsheet/Calculation/LookupRef/RowColumnInformation.php
+++ b/src/PhpSpreadsheet/Calculation/LookupRef/RowColumnInformation.php
@@ -41,7 +41,7 @@ public static function COLUMN($cellAddress = null, ?Cell $cell = null)
             }
         }
 
-        [, $cellAddress] = Worksheet::extractSheetTitle($cellAddress, true);
+        [, $cellAddress] = Worksheet::extractSheetTitle((string) $cellAddress, true);
         if (strpos($cellAddress, ':') !== false) {
             [$startAddress, $endAddress] = explode(':', $cellAddress);
             $startAddress = preg_replace('/[^a-z]/i', '', $startAddress);
@@ -121,17 +121,18 @@ public static function ROW($cellAddress = null, ?Cell $pCell = null)
             }
         }
 
-        [, $cellAddress] = Worksheet::extractSheetTitle($cellAddress, true);
+        [, $cellAddress] = Worksheet::extractSheetTitle((string) $cellAddress, true);
         if (strpos($cellAddress, ':') !== false) {
             [$startAddress, $endAddress] = explode(':', $cellAddress);
             $startAddress = preg_replace('/\D/', '', $startAddress);
             $endAddress = preg_replace('/\D/', '', $endAddress);
-            $returnValue = [];
-            do {
-                $returnValue[][] = (int) $startAddress;
-            } while ($startAddress++ != $endAddress);
 
-            return $returnValue;
+            return array_map(
+                function ($value) {
+                    return [$value];
+                },
+                range($startAddress, $endAddress)
+            );
         }
         [$cellAddress] = explode(':', $cellAddress);