validation for float input

wxPython Users
1

Hello,

I'm a newbie, but I've succeeded in getting a decent application up and running (http://stv.sourceforge.net), thanks to the extensive examples that come with wxPython. I have a question about validating user input.

In my app I ask the user for a float. To validate, I override the default OK button processing in the dialog. Here is an example for making sure that the user entered a float:

   def OnOK(self, event):
       if re.search("^\s*(\d+|\d*\.\d+|\d+\.\d*)\s*$", self.Cutoff):
           event.Skip()
       else:
           dlg = wx.MessageDialog(self.Cutoff must be a float.",
                                  "", wx.OK | wx.ICON_INFORMATION)
           dlg.ShowModal()
           dlg.Destroy()

This seems easier than using other validation methods. I tried the masked text controls, but I don't like how the control is initialized with spaces.

Any comments on the above?

Jeff

2

What about simply converting the value entered, like:

    def OnOK(self, event):
        try:
             val = float(self.Cutoff)
             event.Skip()
        except: # or except ValueError:
             dlg = ...
             ...

Note, float() ignores leading and trailing white spaces.

/Jean Brouwers

Jeffrey O'Neill wrote:

···

Hello,

I'm a newbie, but I've succeeded in getting a decent application up and running (http://stv.sourceforge.net), thanks to the extensive examples that come with wxPython. I have a question about validating user input.

In my app I ask the user for a float. To validate, I override the default OK button processing in the dialog. Here is an example for making sure that the user entered a float:

  def OnOK(self, event):
      if re.search("^\s*(\d+|\d*\.\d+|\d+\.\d*)\s*$", self.Cutoff):
          event.Skip()
      else:
          dlg = wx.MessageDialog(self.Cutoff must be a float.",
                                 "", wx.OK | wx.ICON_INFORMATION)
          dlg.ShowModal()
          dlg.Destroy()

This seems easier than using other validation methods. I tried the masked text controls, but I don't like how the control is initialized with spaces.

Any comments on the above?

Jeff

3

The easiest (and most reliable) I know is:

try:
  val = float(inputstring)
except ValueError:
  # inputstring is not a valid float literal
  HandleTheError

-Chris

Christopher Barker, Ph.D.
Oceanographer
                                         
NOAA/OR&R/HAZMAT (206) 526-6959 voice
7600 Sand Point Way NE (206) 526-6329 fax
Seattle, WA 98115 (206) 526-6317 main reception

Chris.Barker@noaa.gov

···

On Thursday, January 8, 2004, at 11:34 AM, Jeffrey O'Neill wrote:

In my app I ask the user for a float. To validate, I override the default OK button processing in the dialog. Here is an example for making sure that the user entered a float:

  def OnOK(self, event):
      if re.search("^\s*(\d+|\d*\.\d+|\d+\.\d*)\s*$", self.Cutoff):
          event.Skip()
      else:
          dlg = wx.MessageDialog(self.Cutoff must be a float.",
                                 "", wx.OK | wx.ICON_INFORMATION)
          dlg.ShowModal()
          dlg.Destroy()