Asked By – Chuck Testa
This “underscoring” seems to occur a lot, and I was wondering if this was a requirement in the Python language, or merely a matter of convention?
Also, could someone name and explain which functions tend to have the underscores, and why (
__init__, for instance)?
Now we will see solution for issue: Why do some functions have underscores “__” before and after the function name?
The following special forms using leading or trailing underscores are
recognized (these can generally be combined with any case convention):
_single_leading_underscore: weak “internal use” indicator. E.g.
from M import *does not import objects whose name starts with an underscore.
single_trailing_underscore_: used by convention to avoid conflicts with Python keyword, e.g.
__double_leading_underscore: when naming a class attribute, invokes name mangling (inside class FooBar,
_FooBar__boo; see below).
__double_leading_and_trailing_underscore__: “magic” objects or attributes that live in user-controlled namespaces. E.g.
__file__. Never invent such names; only use them as documented.
Note that names with double leading and trailing underscores are essentially reserved for Python itself: “Never invent such names; only use them as documented”.