Data commit

Task/Pointers-and-references/Python/pointers-and-references.py

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+ # Bind a literal string object to a name:
+ a = "foo"
+ # Bind an empty list to another name:
+ b = []
+ # Classes are "factories" for creating new objects: invoke class name as a function:
+ class Foo(object):
+     pass
+ c = Foo()
+ # Again, but with optional initialization:
+ class Bar(object):
+     def __init__(self, initializer = None)
+         # "initializer is an arbitrary identifier, and "None" is an arbitrary default value
+         if initializer is not None:
+            self.value = initializer
+ d = Bar(10)
+ print d.value
+ # Test if two names are references to the same object:
+ if a is b: pass
+ # Alternatively:
+ if id(a) == id(b): pass
+ # Re-bind a previous used name to a function:
+ def a(fmt, *args):
+     if fmt is None:
+         fmt = "%s"
+      print fmt % (args)
+ # Append reference to a list:
+ b.append(a)
+ # Unbind a reference:
+ del(a)
+ # Call (anymous function object) from inside a list
+ b[0]("foo")  # Note that the function object we original bound to the name "a" continues to exist
+              # even if its name is unbound or rebound to some other object.