add method propEq

README.md

@@ -386,7 +386,22 @@ R.project(['v1'], [obj1, obj2]) # [{'v1': 1}, {'v1': 3}]
 
 - [ ] promap
 - [x] prop
-- [ ] propEq
+- [x] propEq
+
+```python
+# works for both dict and object
+class Obj:
+  def __init__(self, v1, v2):
+    self.v1 = v1
+    self.v2 = v2
+obj1 = Obj(1, 2)
+R.propEq(1, 'v1', obj1) # True
+R.propEq(2, 'v2', obj1) # True
+R.propEq(1, 'v2', obj1) # False
+
+R.propEq(1, 'v1', {'v1': 1}) # True
+```
+
 - [ ] propIs
 - [ ] propOr
 - [x] props

ramda/__init__.py

@@ -61,6 +61,7 @@
 from .product import product
 from .project import project
 from .prop import prop
+from .propEq import propEq
 from .props import props
 from .range import range
 from .reduce import reduce

ramda/propEq.py

@@ -0,0 +1,10 @@
+from .equals import equals
+from .private._curry3 import _curry3
+from .prop import prop
+
+
+def inner_propEq(val, name, obj):
+  return equals(val, prop(name, obj))
+
+
+propEq = _curry3(inner_propEq)

test/test_propEq.py

@@ -0,0 +1,55 @@
+
+import unittest
+
+import ramda as R
+
+from .helpers.Maybe import Just
+
+"""
+https://github.com/ramda/ramda/blob/master/test/propEq.js
+"""
+
+dict1 = {'name': 'Abby', 'age': 7, 'hair': 'blond'}
+dict2 = {'name': 'Fred', 'age': 12, 'hair': 'brown'}
+
+
+class TestPropEq(unittest.TestCase):
+  def test_has_R_equals_semantics(self):
+    # TODO: handle minus zero
+    self.assertEqual(True, R.propEq(float('nan'), 'value', {'value': float('nan')}))
+    self.assertEqual(True, R.propEq(Just([42]), 'value', {'value': Just([42])}))
+
+  def test_returns_False_if_called_with_None(self):
+    self.assertEqual(False, R.propEq('Abby', 'name', None))
+
+class TestPropEqForDict(unittest.TestCase):
+  def test_determines_whether_a_particular_property_matches_a_given_value_for_a_specific_object(self):
+    self.assertEqual(True, R.propEq('Abby', 'name', dict1))
+    self.assertEqual(True, R.propEq('brown', 'hair', dict2))
+    self.assertEqual(False, R.propEq('blond', 'hair', dict2))
+
+class TestPropEqForObject(unittest.TestCase):
+  def test_determines_whether_a_particular_property_matches_a_given_value_for_a_specific_object(self):
+    class Person:
+      def __init__(self, name, age, hair):
+        self.name = name
+        self.age = age
+        self.hair = hair
+    abby = Person('Abby', 7, 'blond')
+    fred = Person('Fred', 12, 'brown')
+    self.assertEqual(True, R.propEq('Abby', 'name', abby))
+    self.assertEqual(True, R.propEq('brown', 'hair', fred))
+    self.assertEqual(False, R.propEq('blond', 'hair', fred))
+
+class TestPropEqForList(unittest.TestCase):
+  def test_handles_number_as_property(self):
+    deities=['Cthulhu', 'Dagon', 'Yog-Sothoth']
+    self.assertEqual(True, R.propEq('Cthulhu', 0, deities))
+    self.assertEqual(True, R.propEq('Dagon', 1, deities))
+    self.assertEqual(True, R.propEq('Yog-Sothoth', 2, deities))
+    self.assertEqual(True, R.propEq('Yog-Sothoth', -1, deities))
+    self.assertEqual(True, R.propEq(None, 3, deities))
+
+
+if __name__ == '__main__':
+  unittest.main()