Changes between Version 3 and Version 4 of PortingNotesFor2To3

Timestamp:

Dec 10, 2011, 8:07:31 AM (13 years ago)

Author:

Vinay Sajip

Comment:

--

PortingNotesFor2To3

@@ -45 +45 @@
 
 * If you have classes with metaclasses, change them to use the form `MyClassWithMetaClass(with_metaclass(MetaClass, BaseClass):`
-  where you can omit `BaseClass` if it is `object`.
+  where you can omit `BaseClass` if it is `object`. Remove the `__metaclass__ = XXX` statement from the class body (replacing it with
+  `pass` if that's all there was in the class body).
 
 * If you need to reraise an exception, do `from django.utils.py3 import reraise` and invoke it using the form
   `reraise(type, instance, traceback)`.
+
+* You will see that `2to3` puts `list()` around calls to methods named `keys`, `values` or `items`. This is sometimes but not always
+  necessary, so examine each on a case-by-case basis. In particular, if `values` is called on a queryset, you '''don't''' want to
+  wrap with `list()`.
+
+* There are functions `iterkeys`, `itervalues` and `iteritems` defined in `django.utils.py3`. Import them if there is any reference
+  to those methods, and replace using the pattern `x.iterkeys()` -> `iterkeys(x)` (where `x` might be an expression rather than just
+  a name).
+
+* Replace `map` calls with the list comprehensions suggested by `2to3`. If you see `map(None, ...)` you will need to import and use
+  `izip_longest` from `django.utils.py3`.
+
+* If you see `xrange` in the source, just do `from django.utils.py3 import xrange`.
+
+* If you use anything from `urllib`, `urllib2`, `urlparse`, you will need to import them