Merge pull request #18 from dieterpl/palindrome_checker

abranhe · web-flow · commit 9eba429a9ea0 · 2018-10-10T22:27:27.000-04:00
Added a palindrome checker
diff --git a/allalgorithms/string/__init__.py b/allalgorithms/string/__init__.py
@@ -0,0 +1,2 @@
+from .palindrome_check import *
+
diff --git a/allalgorithms/string/palindrome_check.py b/allalgorithms/string/palindrome_check.py
@@ -0,0 +1,17 @@
+# -*- coding: UTF-8 -*-
+#
+# Checks if string is a palindrome 
+# The All ▲lgorithms library for python
+#
+# Contributed by: dieterpl
+# Github: @dieterpl
+#
+import re
+
+def palindrome_check(s):
+    s = re.sub(r'[^\w]', '', s)
+    if len(s) < 2:
+        return True
+    if s[0].lower() != s[-1].lower():
+        return False
+    return palindrome_check(s[1:-1])
diff --git a/changelog.md b/changelog.md
@@ -32,4 +32,7 @@ Added:
   - Insertion Sort
   - Pigeonhole Sort
   - Selection Sort
-  - Stooge Sort
+  - Stooge Sort
+
+- ### String
+  - Palindrome Checker
diff --git a/docs/string/palindrome-check.md b/docs/string/palindrome-check.md
@@ -0,0 +1,36 @@
+# Palindrome Check
+
+A palindrome is a word, number, phrase, or other sequence of characters which reads the same backward as forward, such as madam or racecar or the number 10201. (Wikipedia)
+
+## Install
+
+```
+pip install allalgorithms
+```
+
+## Usage
+
+```py
+from allalgorithms.string import palindrome_check
+
+str = "10201"
+
+print(palindrome_check(str)
+# -> True
+
+str = "test"
+
+print(palindrome_check(str)
+# -> False
+```
+
+## API
+
+### palindrome_check(string)
+
+> Return True if string is a palindrome, False otherwise
+
+##### Params:
+
+- `string`: Input String
+
diff --git a/readme.md b/readme.md
@@ -70,6 +70,8 @@ print(binary_search(arr, 3))
   - [Pigeonhole Sort](https://python.allalgorithms.com/sorting/pigeonhole-sort)
   - [Selection Sort](https://python.allalgorithms.com/sorting/selection-sort)
   - [Stooge Sort](https://python.allalgorithms.com/sorting/stooge-sort)
+- ### String
+  - [Palindrome Check](https://python.allalgorithms.com/string/palindrom-check)
 
 # Related
 
diff --git a/tests/test_string.py b/tests/test_string.py
@@ -0,0 +1,17 @@
+import unittest
+
+from allalgorithms.string import palindrome_check
+
+
+class TestSorting(unittest.TestCase):
+
+    def test_palindrome_check(self):
+        self.assertEqual(True, palindrome_check("a"))
+        self.assertEqual(True, palindrome_check("10201"))
+        self.assertEqual(False, palindrome_check("test"))
+        self.assertEqual(True, palindrome_check("Mr. Owl ate my metal worm"))
+        self.assertEqual(True, palindrome_check("Was it a car or a cat I saw?"))
+        self.assertEqual(False, palindrome_check("How are you?"))
+
+if __name__ == "__main__":
+    unittest.main()

Original file line number	Diff line number	Diff line change
`@@ -0,0 +1,2 @@`
	`1`	`+from .palindrome_check import *`
	`2`	`+`