From afc1a46306a5b0c73a153649d02ca9ee639eb97d Mon Sep 17 00:00:00 2001
From: zyd <zydmayday@gmail.com>
Date: Sun, 21 Aug 2022 08:59:59 +0900
Subject: [PATCH] add method maxBy

---
 README.md          |  2 +-
 ramda/__init__.py  |  1 +
 ramda/maxBy.py     | 10 ++++++++++
 test/test_maxBy.py | 17 +++++++++++++++++
 4 files changed, 29 insertions(+), 1 deletion(-)
 create mode 100644 ramda/maxBy.py
 create mode 100644 test/test_maxBy.py

diff --git a/README.md b/README.md
index e450739..cf1682e 100644
--- a/README.md
+++ b/README.md
@@ -489,7 +489,7 @@ we will compare with str(a) and str(b).
 R.Max('A', None) # None, 'A' < 'None'
 ```
 
-- [ ] maxBy
+- [x] maxBy
 - [ ] mean
 - [ ] median
 - [ ] memoizeWith
diff --git a/ramda/__init__.py b/ramda/__init__.py
index 085e071..c6c4a8f 100644
--- a/ramda/__init__.py
+++ b/ramda/__init__.py
@@ -78,6 +78,7 @@
 from .match import match
 from .mathMod import mathMod
 from .Max import Max
+from .maxBy import maxBy
 from .Min import Min
 from .modulo import modulo
 from .multiply import multiply
diff --git a/ramda/maxBy.py b/ramda/maxBy.py
new file mode 100644
index 0000000..90a7450
--- /dev/null
+++ b/ramda/maxBy.py
@@ -0,0 +1,10 @@
+from .Max import Max
+from .private._curry3 import _curry3
+
+
+def inner_maxBy(f, a, b):
+  resultB = f(b)
+  return b if Max(f(a), resultB) == resultB else a
+
+
+maxBy = _curry3(inner_maxBy)
diff --git a/test/test_maxBy.py b/test/test_maxBy.py
new file mode 100644
index 0000000..02e463c
--- /dev/null
+++ b/test/test_maxBy.py
@@ -0,0 +1,17 @@
+import unittest
+
+import ramda as R
+
+"""
+https://github.com/ramda/ramda/blob/master/test/maxBy.js
+"""
+
+
+class TestMaxBy(unittest.TestCase):
+  def test_returns_the_larger_value_as_determined_by_the_function(self):
+    self.assertEqual(-3, R.maxBy(lambda x: x * x, -3, 2))
+    self.assertEqual({'x': 5, 'y': 10}, R.maxBy(R.prop('x'), {'x': 3, 'y': 1}, {'x': 5, 'y': 10}))
+
+
+if __name__ == '__main__':
+  unittest.main()