Python single/double underline use

In Python programming, you will often encounter functions (function), methods, and attributes (attribute) with the underscore ' _ ' as the prefix, and here is a summary.

There are four main cases:

1 #  Public 2 __object__ # Special, Python system use, user should not define like it 3 __object # Private (name mangling during runtime) 4 # Obey Python Coding convention, consider it as private

1 and 22 situations are easier to understand, not much to explain, and the most confusing are 3 and 4 situations. Before explaining the 3 and 4 scenarios, first understand Python's description of private, there is no concept of protected in Python, either public or private, but the private in Python is not like C + +, Java, It is not a true private, and by name Mangling (name adaptation, the following example illustrates) The mechanism can access private.

1 classFoo ():2     def __init__():3         ... 4     defPublic_method ():5         Print 'This was public method'6     def __fullprivate_method():7         Print 'This is double underscore leading method'8     def_halfprivate_method ():9         Print 'This is one underscore leading method'Ten  Onef =Foo () AF.public_method ()#OK -F.__fullprivate_method()#Error occur -F._halfprivate_method ()#OK

As explained above, Python does not have a real sense of private, see the following methods to access the __fullprivate_method ()

　　

Python single/double underline use