[Python-ideas] Re: Ampersand operator for strings
Rob Cliffe writes: > Perhaps where you're not laying out a table, I'm an economist, laying out tables is what I do. :-) Getting serious: > but constructing a human-readable string? So > s1 + ' ' + s2 + ' ' + s3 > or > ' '.join((s1, s3, s3)) > would become > s1 & s2 & s3 > saving you a bit of typing. Just sayin'. str '+' has long been quite rare in my coding. str concatenation is almost never in an inner loop, or slighly more complex formatting is the point. f-strings and .format save you the type conversion to str. So I don't find that occasional saving at all interesting. A vanishingly small number of my str constructions involve only strs with trivial formatting. What interests me about the proposal is the space-collapsing part, which a naive f-string would do incorrectly if, say, s2 == '' or s3 == '\t\t\ttabs to the left of me'. But where does this space-surrounded str data come from? Steve ___ Python-ideas mailing list -- python-ideas@python.org To unsubscribe send an email to python-ideas-le...@python.org https://mail.python.org/mailman3/lists/python-ideas.python.org/ Message archived at https://mail.python.org/archives/list/python-ideas@python.org/message/HTEPBAI6EKXTUSU5SYZDZJUCOWHQN6C7/ Code of Conduct: http://python.org/psf/codeofconduct/
[Python-ideas] Re: Ampersand operator for strings
On 06/03/2023 15:49, Stephen J. Turnbull wrote: Steven D'Aprano writes: > I like the look of the & operator for concatenation, so I want to like > this proposal. But I think I will need to see real world code to > understand when it would be useful. I have to second that motion. Pretty much any time I'm constructing lines containing variable text, each string value arrives stripped and I far more often want padding of variable width values rather than space compression. Understood. But perhaps in (the tiny minority? of) cases where you *don't* want padding, you would like single space separators? Perhaps where you're not laying out a table, but constructing a human-readable string? So s1 + ' ' + s2 + ' ' + s3 or ' '.join((s1, s3, s3)) would become s1 & s2 & s3 saving you a bit of typing. Just sayin'. Best wishes Rob Cliffe I admit that I use M-SPC (aka just-one-space) lot in Emacsen, but I can't recall wanting it in a program in any language. ___ Python-ideas mailing list -- python-ideas@python.org To unsubscribe send an email to python-ideas-le...@python.org https://mail.python.org/mailman3/lists/python-ideas.python.org/ Message archived at https://mail.python.org/archives/list/python-ideas@python.org/message/DZXQJ4GQTDEEMOO6VX4VJE45ZN7XNMR4/ Code of Conduct: http://python.org/psf/codeofconduct/ ___ Python-ideas mailing list -- python-ideas@python.org To unsubscribe send an email to python-ideas-le...@python.org https://mail.python.org/mailman3/lists/python-ideas.python.org/ Message archived at https://mail.python.org/archives/list/python-ideas@python.org/message/5W6E6JU7Y7BWYG26YFVKUXU2RCCMGQWJ/ Code of Conduct: http://python.org/psf/codeofconduct/
[Python-ideas] Re: Ampersand operator for strings
Steven D'Aprano writes: > I like the look of the & operator for concatenation, so I want to like > this proposal. But I think I will need to see real world code to > understand when it would be useful. I have to second that motion. Pretty much any time I'm constructing lines containing variable text, each string value arrives stripped and I far more often want padding of variable width values rather than space compression. I admit that I use M-SPC (aka just-one-space) lot in Emacsen, but I can't recall wanting it in a program in any language. ___ Python-ideas mailing list -- python-ideas@python.org To unsubscribe send an email to python-ideas-le...@python.org https://mail.python.org/mailman3/lists/python-ideas.python.org/ Message archived at https://mail.python.org/archives/list/python-ideas@python.org/message/DZXQJ4GQTDEEMOO6VX4VJE45ZN7XNMR4/ Code of Conduct: http://python.org/psf/codeofconduct/
[Python-ideas] Re: Ampersand operator for strings
On Mon, Mar 6, 2023 at 7:37 AM Steven D'Aprano wrote: > (...) > I like the look of the & operator for concatenation, so I want to like > this proposal. But I think I will need to see real world code to > understand when it would be useful. > I'd say we paint the shed blue. I mean - maybe "|" is more pleasant when thinking about concatenation. > > > -- > Steve > > ___ Python-ideas mailing list -- python-ideas@python.org To unsubscribe send an email to python-ideas-le...@python.org https://mail.python.org/mailman3/lists/python-ideas.python.org/ Message archived at https://mail.python.org/archives/list/python-ideas@python.org/message/LYZ3ZAQNIUP3CCNWDGZWYAGBFLUFPHK2/ Code of Conduct: http://python.org/psf/codeofconduct/
[Python-ideas] Re: Ampersand operator for strings
On Mon, Mar 6, 2023 at 12:51 AM David Mertz, Ph.D.
wrote:
> Is it really that much longer to write `f"{s1} {s2}"` when you want that?
>
As for being that much longer: yes it is.
The more important factor is, I think, the increase in complexity +
readabiity for default strings is worth it in this case.
One nice thing to think about might be how to make string subclassing to be
more useful - so this kind of thing could be done for whoever needs it in
one more idiomatic project. The drawback is how cumbersome it is to
instantiate a string subclass compared to a string literal. (I just got an
idea, but it would be too offtopic here - if I think it is worth, I will
post it in a new thread later)
>
> Maybe a couple characters more total, but once you are in an f-string, you
> can also do a zillion other things at the same time.
>
> On Sun, Mar 5, 2023 at 10:42 PM Rob Cliffe via Python-ideas <
> python-ideas@python.org> wrote:
>
>> Tl;dr: Join strings together with exactly one space between non-blank
>> text where they join.
>>
>> I propose a meaning for
>> s1 & s2
>> where s1 and s2 are strings.
>> Namely, that it should be equivalent to
>> s1.rstrip() + (' ' if (s1.strip() and s2.strip()) else '') +
>> s2.lstrip()
>> Informally, this will join the two strings together with exactly one space
>> between the last non-blank text in s1 and the first non-blank text in s2.
>> Example: " bar " & "foo"==" bar
>> foo"
>>
>> This operator is associative, so there is no ambiguity in expressions
>> such as
>> s1 & s2 & s3
>> There *is* a possible ambiguity in expressions such as
>> s1 & s2 + s3
>> where the relative precedence of `&` and `+` matters when s2 consists
>> solely of white space. E.g.
>> " A " & " " + " C" would evaluate
>> to " A C"
>> not to " A C"
>> because `+` has a higher precedence than '&'.
>>
>> Utility:
>> In decades of experience with another language which had such an
>> operator
>> (spelt differently) I have frequently found it useful for
>> constructing
>> human-readable output (e.g. log output, debug/error messages,
>> on-screen labels).
>>
>> Cognitive burden:
>> This would of course be one more thing to learn.
>> But I suggest that it is fairly intuitive that
>> s1 + s2
>> s1 & s2
>> both suggest that two strings are being combined in some way.
>>
>> Bars to overcome:
>> This change would require no fundamental change to Python;
>> just adding an `__and__ function to the str class.
>>
>> Backward compatibility:
>> Given that `str1 & str2` currently raises TypeError,
>> this change would be close to 100% backward-compatible.
>>
>> Alternative meanings:
>> As far as I know nobody has ever suggested an alternative meaning
>> for `&` on strings.
>>
>> Bikeshedding:
>> (1) I don't think it is important for the utility of this change
>> whether `&` strips off all whitespace, or just spaces.
>> I think it is better if it strips off all whitespace,
>> so that it can be understood as working similarly to strip().
>> (2) The definition could be simplified to
>> s1.rstrip() + ' ' + s2.lstrip()
>> (leave an initial/final space when one string is whitespace
>> only).
>> Again the operator would be associative.
>> Again I don't think this is important.
>>
>> Rob Cliffe
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>
>
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[Python-ideas] Re: Ampersand operator for strings
On 06.03.2023 11:33, Steven D'Aprano wrote: On Mon, Mar 06, 2023 at 10:33:26AM +0100, Marc-Andre Lemburg wrote: def join_words(list_of_words) return ' '.join([x.strip() for x in list_of_words]) That's not Rob's suggestion either. I know, but as I mentioned, I use the above often, whereas I find Rob's definition not very intuitive or useful. Rob's suggestion is an operator which concats two substrings with exactly one space between them, without stripping leading or trailing whitespace of the result. Examples: a = "\nHeading:" b = "Result\n\n" a & b would give "\nHeading: Result\n\n" s = "my hovercraft\n" t = "is full of eels\n" s & t would give "my hovercraft is full of eels\n" I find the concept is very easy to understand: "concat with exactly one space between the operands". But I must admit I'm struggling to think of cases where I would use it. I like the look of the & operator for concatenation, so I want to like this proposal. But I think I will need to see real world code to understand when it would be useful. -- Marc-Andre Lemburg eGenix.com Professional Python Services directly from the Experts (#1, Mar 06 2023) >>> Python Projects, Coaching and Support ...https://www.egenix.com/ >>> Python Product Development ...https://consulting.egenix.com/ ::: We implement business ideas - efficiently in both time and costs ::: eGenix.com Software, Skills and Services GmbH Pastor-Loeh-Str.48 D-40764 Langenfeld, Germany. CEO Dipl.-Math. Marc-Andre Lemburg Registered at Amtsgericht Duesseldorf: HRB 46611 https://www.egenix.com/company/contact/ https://www.malemburg.com/ ___ Python-ideas mailing list -- python-ideas@python.org To unsubscribe send an email to python-ideas-le...@python.org https://mail.python.org/mailman3/lists/python-ideas.python.org/ Message archived at https://mail.python.org/archives/list/python-ideas@python.org/message/E7DCRBG5I7RJPIHWSNDZPEBG7UVJEGMR/ Code of Conduct: http://python.org/psf/codeofconduct/
[Python-ideas] Re: Ampersand operator for strings
On Mon, Mar 06, 2023 at 10:33:26AM +0100, Marc-Andre Lemburg wrote: > def join_words(list_of_words) > return ' '.join([x.strip() for x in list_of_words]) That's not Rob's suggestion either. Rob's suggestion is an operator which concats two substrings with exactly one space between them, without stripping leading or trailing whitespace of the result. Examples: a = "\nHeading:" b = "Result\n\n" a & b would give "\nHeading: Result\n\n" s = "my hovercraft\n" t = "is full of eels\n" s & t would give "my hovercraft is full of eels\n" I find the concept is very easy to understand: "concat with exactly one space between the operands". But I must admit I'm struggling to think of cases where I would use it. I like the look of the & operator for concatenation, so I want to like this proposal. But I think I will need to see real world code to understand when it would be useful. -- Steve ___ Python-ideas mailing list -- python-ideas@python.org To unsubscribe send an email to python-ideas-le...@python.org https://mail.python.org/mailman3/lists/python-ideas.python.org/ Message archived at https://mail.python.org/archives/list/python-ideas@python.org/message/2OZXSXETHQLWJQYAM2S3SJVACPEIPDSZ/ Code of Conduct: http://python.org/psf/codeofconduct/
[Python-ideas] Re: Ampersand operator for strings
On 02.03.2023 18:27, Rob Cliffe via Python-ideas wrote:
Tl;dr: Join strings together with exactly one space between non-blank
text where they join.
I propose a meaning for
s1 & s2
where s1 and s2 are strings.
Namely, that it should be equivalent to
s1.rstrip() + (' ' if (s1.strip() and s2.strip()) else '') +
s2.lstrip()
Informally, this will join the two strings together with exactly one space
between the last non-blank text in s1 and the first non-blank text in s2.
Example: " bar " & " foo " == " bar
foo "
I don't find these semantics particularly intuitive. Python already has
the + operator for concatenating strings and this doesn't apply any
stripping.
If you're emphasizing on joining words with single space delimiters,
then the usual:
def join_words(list_of_words)
return ' '.join([x.strip() for x in list_of_words])
works much better. You can also apply this recursively, if needed, or
add support for list_of_phrases (first splitting these into a
list_of_words).
The advantage of join_words() is that it's easy to understand and
applies stripping in a concise way. I use such helpers all the time.
--
Marc-Andre Lemburg
eGenix.com
Professional Python Services directly from the Experts (#1, Mar 06 2023)
>>> Python Projects, Coaching and Support ...https://www.egenix.com/
>>> Python Product Development ...https://consulting.egenix.com/
::: We implement business ideas - efficiently in both time and costs :::
eGenix.com Software, Skills and Services GmbH Pastor-Loeh-Str.48
D-40764 Langenfeld, Germany. CEO Dipl.-Math. Marc-Andre Lemburg
Registered at Amtsgericht Duesseldorf: HRB 46611
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