pylib/util.py

@@ -181,6 +181,34 @@ def oomsbetweenunits(a, b):
     return abs((a - b) * 3)
 
 
+def breaknumberstring(value):
+    "Breaks a number string into (aboveDecimal, belowDecimal, isNegative?)"
+    if value[0] == "-":
+        value = value[1:]
+        negative = True
+    else:
+        negative = False
+    if "." in value:
+        above, below = value.split(".")
+    else:
+        above = value
+        below = ""
+    return (above, below, negative)
+
+
+def gluenumberstring(above, below, isnegative):
+    "Glues together parts of a number string"
+    if above == "":
+        above = "0"
+    if len(below) > 0:
+        newvalue = ".".join((above, below))
+    else:
+        newvalue = above
+    if isnegative is True:
+        newvalue = "-" + newvalue
+    return newvalue
+
+
 def rescalestring(value, unitsscaled):
     "Rescale a number string by a given number of units"
     if unitsscaled == 0:

tests/pylib/test_util.py

@@ -211,5 +211,38 @@ class TestPylibUtilMethods(unittest.TestCase):
         # ditto, negative
         self.assertEqual(f("-1.23456", -2), "-1234560")
 
+    def test_breaknumberstring(self):
+        f = ntp.util.breaknumberstring
+
+        # No decimals, positive
+        self.assertEqual(f("1234567890"), ("1234567890", "", False))
+        # ditto, negative
+        self.assertEqual(f("-1234567890"), ("1234567890", "", True))
+        # No whole, positive
+        self.assertEqual(f(".12345"), ("", "12345", False))
+        # ditto, negative
+        self.assertEqual(f("-.12345"), ("", "12345", True))
+        # Both sides, position
+        self.assertEqual(f("123.456"), ("123", "456", False))
+        # ditto, negative
+        self.assertEqual(f("-123.456"), ("123", "456", True))
+
+    def test_gluenumberstring(self):
+        f = ntp.util.gluenumberstring
+
+        # No decimals, positive
+        self.assertEqual(f("123", "", False), "123")
+        # ditto, negative
+        self.assertEqual(f("123", "", True), "-123")
+        # No whole, positive
+        self.assertEqual(f("", "456", False), "0.456")
+        # ditto, negative
+        self.assertEqual(f("", "456", True), "-0.456")
+        # Both sides, positive
+        self.assertEqual(f("123", "456", False), "123.456")
+        # ditto, negative
+        self.assertEqual(f("123", "456", True), "-123.456")
+
+
 if __name__ == '__main__':
     unittest.main()