Dear Developers,
After some findings and further thoughts through this thread, I have
formulated a proposal as follows. (I thank everyone who has commented
in this thread). For the necessary definitions, please look at
https://docs.python.org/3/reference/expressions.html#subscriptions
https://d
Dear ChrisA, Steve,
Thank you for your comments.
ChrisA, it was off the main topic, but for me, the issue was just one
of wording in the exception message. It's good to hear changes to
wording can be done without compatibility concerns. I'll find out
about merge request suggested by Stephen J. Tu
Matsuoka Takuo writes:
> >>> *(1,2),
> (1, 2)
Yes, this works, and now that I see you just want that to work in
"a[*(1,2),]", I agree, I don't know why that is a syntax error. This
works, of course:
t = *(1,2),
a[t]
(in the sense that if a is a sequence you get a TypeError because th
On Thu, Aug 19, 2021 at 11:27 PM Matsuoka Takuo wrote:
>
> Dear Steve,
>
> Thank you for your detailed explanation.
>
> > > (i.e., it can be mistyped as "s[1,2,]" but without SyntaxError this
> > > time). It would at least be consistent if we got SyntaxError in
> > > both cases (namely, the syn
Dear Steve,
Thank you for your detailed explanation.
> > (i.e., it can be mistyped as "s[1,2,]" but without SyntaxError this
> > time). It would at least be consistent if we got SyntaxError in
> > both cases (namely, the syntax allowed only a single Python
> > expression here), but if we don'
Dear Guido van Rossum,
Thank you for bringing the PEP's to my attention.
The idea of PEP 637 on a[*x] is different from my idea. The PEP's idea
appears making subscription analogous to function calls. In the end,
a[*x] would have been equivalent to
a[tuple(x)]
if the PEP had been adopted. a[*
Matsuoka Takuo :
>
> Now, is "1,2," more boxed up than "*(1,2)," is? The *current* rule
> surely says the former is a tuple at some places and the latter
> is not,
Actually, this was wrong. First of all,
>>> *(1,2),
(1, 2)
Moreover, while the Language Reference says
return_stmt ::= "return"
I believe this is useful since this syntax is developed in some
libraries as an internal DSL. At least I have seen it in pandas, a
library handling tables.
df[(df['a'] < df['b']) & (df['b'] < df['c'])]
df[~df['a'].isin(df['b'])]
df[df['b'].isin(df['a']) & (df['c'] < df['d'])]
More exampl
Matsuoka Takuo writes:
> I don't see any parenthesis nor bracket around "1,2,".
Parentheses are not part of tuple display syntax, with the exception
of "()", the empty tuple. Parenthesis are needed for tuple displays
only to group the display in the context of a larger expression.
This is my
Have you seen PEP 637? IIRC it has discussions on a[] and a[*x]. Note that
it was rejected, but the idea of a[*x] is being resurrected for PEP 646.
On Fri, Aug 13, 2021 at 5:43 AM Matsuoka Takuo
wrote:
> Dear Developers,
>
> Given a subscriptable object s, the intended rule for the notation for
Dear Steve,
Thank you for your thoughts.
To be precise, the sequence of letters "*(1,2)" is not actually a
"starred expression" in the sense of the Python Language, but e.g.,
"*(1,2), "
is. (A comma is trailing.) Please check the definitions here:
https://docs.python.org/3/reference/expressions.
Matsuoka Takuo writes:
> Let me clarify the issue. An optional starred expression (denoted
> "[starred_expression]" in the specification of the syntax) is a
> natural generalization of an expression list (which is not necessarily
> an expression in the Python sense) in the sense that use of th
Thanks 2QdxY4RzWzUUiLuE for your thoughtful response. I shouldn't have
used the word "expression" since it was going to be taken as a Python
term.
Let me clarify the issue. An optional starred expression (denoted
"[starred_expression]" in the specification of the syntax) is a
natural generalizatio
On 2021-08-13 at 23:18:29 +1100,
Matsuoka Takuo wrote:
> Given a subscriptable object s, the intended rule for the notation for
> getting an item of s seems that, for any expression {e}, such as
> "x, ",
> s[{e}]
> (i.e., s[x, ] if {e} is "x, ") means the same as
> s[({e})]
If e is an expres
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