Support siPrefix with no suffix in SpinBox

examples/SpinBox.py

@@ -31,6 +31,8 @@ spins = [
      pg.SpinBox(value=1.0, suffix='V', siPrefix=True, dec=True, step=0.5, minStep=0.01)),
     ("Float with SI-prefixed units,<br>dec step=1.0, minStep=0.001", 
      pg.SpinBox(value=1.0, suffix='V', siPrefix=True, dec=True, step=1.0, minStep=0.001)),
+    ("Float with SI prefix but no suffix",
+     pg.SpinBox(value=1e9, siPrefix=True)),
     ("Float with custom formatting", 
      pg.SpinBox(value=23.07, format='${value:0.02f}',
                 regex='\$?(?P<number>(-?\d+(\.\d+)?)|(-?\.\d+))$')),

pyqtgraph/functions.py

@@ -119,10 +119,27 @@ def siFormat(x, precision=3, suffix='', space=True, error=None, minVal=1e-25, al
 
 def siParse(s, regex=FLOAT_REGEX, suffix=None):
     """Convert a value written in SI notation to a tuple (number, si_prefix, suffix).
-    
+
     Example::
-    
-        siParse('100 μV")  # returns ('100', 'μ', 'V')
+
+        siParse('100 µV")  # returns ('100', 'µ', 'V')
+
+    Note that in the above example, the µ symbol is the "micro sign" (UTF-8
+    0xC2B5), as opposed to the Greek letter mu (UTF-8 0xCEBC).
+
+    Parameters
+    ----------
+    s : str
+        The string to parse.
+    regex : re.Pattern, optional
+        Compiled regular expression object for parsing. The default is a
+        general-purpose regex for parsing floating point expressions,
+        potentially containing an SI prefix and a suffix.
+    suffix : str, optional
+        Suffix to check for in ``s``. The default (None) indicates there may or
+        may not be a suffix contained in the string and it is returned if
+        found. An empty string ``""`` is handled differently: if the string
+        contains a suffix, it is discarded.
     """
     s = asUnicode(s)
     s = s.strip()
@@ -130,15 +147,20 @@ def siParse(s, regex=FLOAT_REGEX, suffix=None):
         if s[-len(suffix):] != suffix:
             raise ValueError("String '%s' does not have the expected suffix '%s'" % (s, suffix))
         s = s[:-len(suffix)] + 'X'  # add a fake suffix so the regex still picks up the si prefix
-        
+
+    # special case: discard any extra characters if suffix is explicitly empty
+    if suffix == "":
+        s += 'X'
+
     m = regex.match(s)
     if m is None:
         raise ValueError('Cannot parse number "%s"' % s)
+
     try:
         sip = m.group('siPrefix')
     except IndexError:
         sip = ''
-    
+
     if suffix is None:
         try:
             suf = m.group('suffix')
@@ -146,8 +168,8 @@ def siParse(s, regex=FLOAT_REGEX, suffix=None):
             suf = ''
     else:
         suf = suffix
-    
-    return m.group('number'), '' if sip is None else sip, '' if suf is None else suf 
+
+    return m.group('number'), '' if sip is None else sip, '' if suf is None else suf
 
 
 def siEval(s, typ=float, regex=FLOAT_REGEX, suffix=None):

pyqtgraph/tests/test_functions.py

@@ -423,6 +423,30 @@ def test_eq():
     assert eq(set(range(10)), set(range(10)))
     assert not eq(set(range(10)), set(range(9)))
 
-    
-if __name__ == '__main__':
-    test_interpolateArray()
+
+@pytest.mark.parametrize("s,suffix,expected", [
+    # usual cases
+    ("100 uV", "V", ("100", "u", "V")),
+    ("100 µV", "V", ("100", "µ", "V")),
+    ("4.2 nV", None, ("4.2", "n", "V")),
+    ("1.2 m", "m", ("1.2", "", "m")),
+    ("1.2 m", None, ("1.2", "", "m")),
+    ("5.0e9", None, ("5.0e9", "", "")),
+    ("2 units", "units", ("2", "", "units")),
+    # siPrefix with explicit empty suffix
+    ("1.2 m", "", ("1.2", "m", "")),
+    ("5.0e-9 M", "", ("5.0e-9", "M", "")),
+    # weirder cases that should return the reasonable thing
+    ("4.2 nV", "nV", ("4.2", "", "nV")),
+    ("4.2 nV", "", ("4.2", "n", "")),
+    ("1.2 j", "", ("1.2", "", "")),
+    ("1.2 j", None, ("1.2", "", "j")),
+    # expected error cases
+    ("100 uV", "v", ValueError),
+])
+def test_siParse(s, suffix, expected):
+    if isinstance(expected, tuple):
+        assert pg.siParse(s, suffix=suffix) == expected
+    else:
+        with pytest.raises(expected):
+            pg.siParse(s, suffix=suffix)

pyqtgraph/widgets/SpinBox.py

@@ -466,7 +466,7 @@ class SpinBox(QtGui.QAbstractSpinBox):
 
         # format the string 
         val = self.value()
-        if self.opts['siPrefix'] is True and len(self.opts['suffix']) > 0:
+        if self.opts['siPrefix'] is True:
             # SI prefix was requested, so scale the value accordingly
 
             if self.val == 0 and prev is not None:
@@ -545,7 +545,7 @@ class SpinBox(QtGui.QAbstractSpinBox):
             return False
             
         # check suffix
-        if suffix != self.opts['suffix'] or (suffix == '' and siprefix != ''):
+        if suffix != self.opts['suffix']:
             return False
            
         # generate value