On 27May2018 09:46, Chris Angelico <ros...@gmail.com> wrote:
On Sun, May 27, 2018 at 9:40 AM, Thomas Jollans <t...@tjol.eu> wrote:
There's nothing special about _, it's just a possible name of a
variable, albeit a very short and entirely uninformative one. Normally,
it's not something you'd actually want to name a variable, of course.
As such, _ has become an idiomatic name for dummy variables, i.e.
something you use when syntax requires you to give a variable name, but
you don't actually want one (probably because you're throwing the
variable away). This mostly happens in generator expressions/list
comprehensions.
Yes, and also in stand-alone 'for' loops where you don't care about
the iteration variable:
for _ in range(3): datafile.skipline()
The only actual significance of this name is that the interactive
interpreter will stash the result of the previous expression in that
variable.
6 * 7
42
_ + 1
43
Other than that, it is simply an ordinary name, but one that has some
conventions attached to it.
Also, various lint tools know that the name "_" is used in this way, and don't
complain that a variable is assigned to and not used if its name is "_".
Cheers,
Cameron Simpson <c...@cskk.id.au>
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