Changes between Version 39 and Version 40 of NewbieMistakes

Timestamp:

Feb 21, 2011, 12:57:24 AM (13 years ago)

Author:

anonymous

Comment:

--

NewbieMistakes

@@ -332 +332 @@
 
 Ensure they have different values - e.g. ADMIN_MEDIA_PREFIX = 'admin-media' and MEDIA_URL = '/media'
+
+
+== Default value and Callables ==
+
+==== Symptom ====
+
+You call a method to set a default value, such as random.randint(), but the value is the same for every new instance of your object.
+
+==== Probable cause ====
+
+Each new instance doesn't call random.randint()
+
+==== Solution ====
+
+Prepend "lambda:" like
+{{{
+MyRandNum = models.CharField(max_length=4, default=lambda:random.randint(1000,9999))
+}}}
+