Website hosting service by Active-Venture.com
  

 Back to Index


3.20.2 The Warnings Filter

The warnings filter controls whether warnings are ignored, displayed, or turned into errors (raising an exception).

Conceptually, the warnings filter maintains an ordered list of filter specifications; any specific warning is matched against each filter specification in the list in turn until a match is found; the match determines the disposition of the match. Each entry is a tuple of the form (action, message, category, module, lineno), where:

 

  • action is one of the following strings:

     
    Value  Disposition 

     

    "error" turn matching warnings into exceptions

     

    "ignore" never print matching warnings

     

    "always" always print matching warnings

     

    "default" print the first occurrence of matching warnings for each location where the warning is issued

     

    "module" print the first occurrence of matching warnings for each module where the warning is issued

     

    "once" print only the first occurrence of matching warnings, regardless of location

     

     

  • message is a string containing a regular expression that the warning message must match (the match is compiled to always be case-insensitive)

     

  • category is a class (a subclass of Warning) of which the warning category must be a subclass in order to match

     

  • module is a string containing a regular expression that the module name must match (the match is compiled to be case-sensitive)

     

  • lineno is an integer that the line number where the warning occurred must match, or 0 to match all line numbers

     

Since the Warning class is derived from the built-in Exception class, to turn a warning into an error we simply raise category(message).

The warnings filter is initialized by -W options passed to the Python interpreter command line. The interpreter saves the arguments for all -W options without interpretation in sys.warnoptions; the warnings module parses these when it is first imported (invalid options are ignored, after printing a message to sys.stderr).

 

  

 

2002-2004 Active-Venture.com Webhosting Service

 

Disclaimer: This documentation is provided only for the benefits of our hosting customers.
For authoritative source of the documentation, please refer to http://python.org/doc/

 

Cheap domain registration : Register domain name or buy domain name, including free domain hosting services

 
Active-Domain.com offers cheap domain registration, domain name transfer and domain search services    

Domain registration : Buy domain name or register domain name from $5.95/year only