From 4d9e6d7e32463c8aa7e3ef7ce8aa10527376bed6 Mon Sep 17 00:00:00 2001
From: Kitaiti Makoto <KitaitiMakoto@gmail.com>
Date: Sun, 7 Jan 2024 06:39:14 +0900
Subject: [PATCH 1/2] :white_check_mark: Add test for DataFrame#to_wide with
 missing values

---
 test/test_data_frame_reshaping.rb | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/test/test_data_frame_reshaping.rb b/test/test_data_frame_reshaping.rb
index 98cf7814..88012236 100644
--- a/test/test_data_frame_reshaping.rb
+++ b/test/test_data_frame_reshaping.rb
@@ -128,5 +128,20 @@ class DataFrameReshapingTest < Test::Unit::TestCase
       df = @df.rename(NAME: :key1, VALUE: :key2)
       assert_equal @str, df.to_wide(name: :key1, value: :key2).to_s
     end
+
+    test '#to_wide with missing values' do
+      df = DataFrame.new(
+        names: %w[name1 name1 name1 name2 name2 name3 name3 name3],
+        NAME: %w[One Two Three One Three One Two Three],
+        VALUE: [1.1, 2.1, 3.1, 1.2, 3.2, 1.3, 2.3, 3.3]
+      )
+      wide = DataFrame.new(
+        names: %w[name1 name2 name3],
+        One: [1.1, 1.2, 1.3],
+        Two: [2.1, nil, 2.3],
+        Three: [3.1, 3.2, 3.3]
+      )
+      assert_equal wide, df.to_wide(fill_missing: true)
+    end
   end
 end

From f498163ed849e1184cc73080d87d410a48609320 Mon Sep 17 00:00:00 2001
From: Kitaiti Makoto <KitaitiMakoto@gmail.com>
Date: Sun, 7 Jan 2024 06:43:09 +0900
Subject: [PATCH 2/2] :zap: Add fill_missing option to DataFrame#to_wide

---
 lib/red_amber/data_frame_reshaping.rb | 18 +++++++++++++++++-
 1 file changed, 17 insertions(+), 1 deletion(-)

diff --git a/lib/red_amber/data_frame_reshaping.rb b/lib/red_amber/data_frame_reshaping.rb
index 567d04f4..c0027ec5 100644
--- a/lib/red_amber/data_frame_reshaping.rb
+++ b/lib/red_amber/data_frame_reshaping.rb
@@ -250,7 +250,7 @@ def to_long(*keep_keys, name: :NAME, value: :VALUE)
     #
     # @since 0.2.0
     #
-    def to_wide(name: :NAME, value: :VALUE)
+    def to_wide(name: :NAME, value: :VALUE, fill_missing: false, fill_with: nil)
       name = name.to_sym
       unless keys.include?(name)
         raise DataFrameArgumentError,
@@ -274,6 +274,22 @@ def to_wide(name: :NAME, value: :VALUE)
         h = converts.to_h
         hash[keeps.to_h][h[name].to_s.to_sym] = h[value]
       end
+      if fill_missing
+        names = [].union(*hash.values.collect(&:keys))
+        hash.each_pair do |ns, vs|
+          next if vs.length == names.length
+
+          keys = vs.keys
+          values = vs.values
+          names.each_with_index do |n, i|
+            next if vs.key?(n)
+
+            keys.insert(i, n)
+            values.insert(i, fill_with)
+          end
+          hash[ns] = keys.zip(values).to_h
+        end
+      end
       ks = hash.first[0].keys + hash.first[1].keys
       vs = hash.map { |k, v| k.values + v.values }.transpose
       DataFrame.new(ks.zip(vs))