Why does python use two underscores for certain things?

Question

I\'m fairly new to actual programming languages, and Python is my first one. I know my way around Linux a bit, enough to get a summer job with it (I\'m still in high school)

Answer 1

[Speculation] Python was influenced by Algol68, Guido possibly used Algol68 at the University of Amsterdam where Algol68 has a similar "stropping regime" called "Quote stropping". In Algol68 the operators, types and keywords can appear in a different typeface (usually **bold**, or __underlined__), in sourcecode files this typeface is achieved with quotes, e.g. 'abs' (quoting similar to quoting in 'wikitext')

Algol68 ⇒ Python (Operators mapped to member functions)

• 'and' ⇒ __and__
• 'or' ⇒ __or__
• 'not' ⇒ not
• 'entier' ⇒ __trunc__
• 'shl' ⇒ __lshift__
• 'shr' ⇒ __rshift__
• 'upb' ⇒ __sizeof__
• 'long' ⇒ __long__
• 'int' ⇒ __int__
• 'real' ⇒ __float__
• 'format' ⇒ __format__
• 'repr' ⇒ __repr__
• 'abs' ⇒ __abs__
• 'minus' ⇒ __neg__
• 'minus' ⇒ __sub__
• 'plus' ⇒ __add__
• 'times' ⇒ __mul__
• 'mod' ⇒ __mod__
• 'div' ⇒ __truediv__
• 'over' ⇒ __div__
• 'up' ⇒ __pow__
• 'im' ⇒ imag
• 're' ⇒ real
• 'conj' ⇒ conjugate

In Algol68 these were refered to as bold names, e.g. abs, but "under-under-abs" __abs__ in python.

My 2 cents: ¢ So sometimes — like a ghost — when you cut and paste python classes into a wiki you will magically reincarnate Algol68's bold keywords. ¢