Determine if a string has all the same characters: Difference between revisions

Content added Content deleted

Inline

@@ Line 268: / Line 268: @@
 "ǞǞǞ" (length: 3), has the same character in all positions.</pre>
+=={{header|Python}}==
+===Functional===
+<lang python>'''Determine if a string has all the same characters'''
+from itertools import groupby
+# firstDifferingCharLR :: String -> Either String Char
+def firstDifferingCharLR(s):
+    '''Either the first character (if any) that differs from
+       the character at the head of string, or a message
+       reporting that no character changes were seen.
+    '''
+    groups = list(groupby(s))
+    return Right(repr(groups[1][0])) if 1 < len(groups) else (
+        Left('No character changes')
+    )
+# TEST ----------------------------------------------------
+# main :: IO ()
+def main():
+    '''Test of 7 strings'''
+    for lr in [firstDifferingCharLR(s) for s in [
+        '',
+        '   ',
+        '2',
+        '333',
+        '.55',
+        'tttTTT',
+        '4444 444'
+    ]]:
+        print(either(lambda l: l)(lambda r: r)(lr))
+# GENERIC -------------------------------------------------
+# either :: (a -> c) -> (b -> c) -> Either a b -> c
+def either(fl):
+    '''The application of fl to e if e is a Left value,
+       or the application of fr to e if e is a Right value.
+    '''
+    return lambda fr: lambda e: fl(e['Left']) if (
+        None is e['Right']
+    ) else fr(e['Right'])
+# Left :: a -> Either a b
+def Left(x):
+    '''Constructor for an empty Either (option type) value
+       with an associated string.
+    '''
+    return {'type': 'Either', 'Right': None, 'Left': x}
+# Right :: b -> Either a b
+def Right(x):
+    '''Constructor for a populated Either (option type) value'''
+    return {'type': 'Either', 'Left': None, 'Right': x}
+# MAIN ---
+if __name__ == '__main__':
+    main()</lang>
+{{Out}}
+<pre>No character changes
+No character changes
+No character changes
+No character changes
+'5'
+'T'
+' '</pre>
 =={{header|REXX}}==