Developpez.com

Python

Choisissez la catégorie, puis la rubrique :

26.4 warnings -- Warning control

26.4 warnings -- Warning control

New in version 2.1.

Warning messages are typically issued in situations where it is useful to alert the user of some condition in a program, where that condition (normally) doesn't warrant raising an exception and terminating the program. For example, one might want to issue a warning when a program uses an obsolete module.

Python programmers issue warnings by calling the warn() function defined in this module. (C programmers use PyErr_Warn(); see the Python/C API Reference Manual for details).

Warning messages are normally written to sys.stderr, but their disposition can be changed flexibly, from ignoring all warnings to turning them into exceptions. The disposition of warnings can vary based on the warning category (see below), the text of the warning message, and the source location where it is issued. Repetitions of a particular warning for the same source location are typically suppressed.

There are two stages in warning control: first, each time a warning is issued, a determination is made whether a message should be issued or not; next, if a message is to be issued, it is formatted and printed using a user-settable hook.

The determination whether to issue a warning message is controlled by the warning filter, which is a sequence of matching rules and actions. Rules can be added to the filter by calling filterwarnings() and reset to its default state by calling resetwarnings().

The printing of warning messages is done by calling showwarning(), which may be overridden; the default implementation of this function formats the message by calling formatwarning(), which is also available for use by custom implementations.



See About this document... for information on suggesting changes.
Les développeurs logiciels actifs sont actuellement estimés à un peu moins de 19 millions dans le monde, 13 millions d'entre eux seraient des pros
Voici l'état de l'écosystème des développeurs en 2019 : l'évolution du monde du code, d'après une enquête menée par Jetbrains
Python 3.8.0 : un aperçu des fonctionnalités attendues pour la version stable du langage de programmation
Apprendre Python et s'initier à la programmation - Partie 2 : Programmation avancée, un cours de Sébastien Combéfis
Contacter le responsable de la rubrique Python

Partenaire : Hébergement Web