Another update from ingydotnet^djgoku

Task/Digital-root/Python/digital-root.py

@@ -1,10 +1,13 @@
-def droot (n):
-    x = [n]
-    while x[-1] > 10:
-        x.append(sum(int(dig) for dig in str(x[-1])))
-    return len(x) - 1, x[-1]
+def digital_root (n):
+    ap = 0
+    n = abs(int(n))
+    while n >= 10:
+        n = sum(int(digit) for digit in str(n))
+        ap += 1
+    return ap, n
 
-for n in [627615, 39390, 588225, 393900588225]:
-    a, d = droot (n)
-    print "%12i has additive persistance %2i and digital root of %i" % (
-        n, a, d)
+if __name__ == '__main__':
+    for n in [627615, 39390, 588225, 393900588225, 55]:
+        persistance, root = digital_root(n)
+        print("%12i has additive persistance %2i and digital root %i."
+              % (n, persistance, root))