Re: [Python-ideas] oneof() and multi split and replace for stirngs
On 1/23/07, Josiah Carlson jcarlson@uci.edu wrote:
Whether it is a tuple being passed, or a "magic" container, I don't think it matters; though I would lean towards a tuple because it is 5 less characters to type out, and one fewer data types to worry about.
I had talked to others and the concensus was against the tuples for ugliness. s.split((a,b), c) wasn't a popular choice, but s.split(oneof(a, b), c) reads better.
This has been discussed before in python-dev, I believe the general consensus was that it would be convenient at times, but I also believe the general consensus was "use re";
It seems like we have a history of useful string operations being moved away from "use re" to "dont use re", such that the slightly recent startswith and endswith methods, and even split and replace themselves. I would like to see less reasons for people to worry with regular expressions until they actually need them. If we can provide a better way to get the job done, that seems like a great idea.
ALSO
The oneof type isn't just a single use thing. Usecode may often make use of it, and other types could benefit such as doing a lookup with d[oneof(1,2,3)] (where order would matter for priority). I think this semantic collection type would be very useful in a number of contexts where we would currently just loop or duplicate code.
"Calvin Spealman" ironfroggy@gmail.com wrote:
On 1/23/07, Josiah Carlson jcarlson@uci.edu wrote:
Whether it is a tuple being passed, or a "magic" container, I don't think it matters; though I would lean towards a tuple because it is 5 less characters to type out, and one fewer data types to worry about.
I had talked to others and the concensus was against the tuples for ugliness. s.split((a,b), c) wasn't a popular choice, but s.split(oneof(a, b), c) reads better.
oneof = tuple
Now it reads better. Stick with tuple.
This has been discussed before in python-dev, I believe the general consensus was that it would be convenient at times, but I also believe the general consensus was "use re";
It seems like we have a history of useful string operations being moved away from "use re" to "dont use re", such that the slightly recent startswith and endswith methods, and even split and replace themselves. I would like to see less reasons for people to worry with regular expressions until they actually need them. If we can provide a better way to get the job done, that seems like a great idea.
Well, startswith and endswith is still computable without re or the methods, and turns out to be faster (for certain startswith and endswith operations) to do...
if st[:X] == sub: or if st[-X:] == sub:
(more specifically, when sub is a constant and X is previously-known)
The oneof type isn't just a single use thing. Usecode may often make use of it, and other types could benefit such as doing a lookup with d[oneof(1,2,3)] (where order would matter for priority). I think this semantic collection type would be very useful in a number of contexts where we would currently just loop or duplicate code.
I took the time to look for a thread discussing something like this feature before. And I found it. Turns out I was wrong: http://mail.python.org/pipermail/python-dev/2005-September/056119.html
That thread discusses an enhancement to str.[r|l|]strip(), where one could specify a list of strings to be trimmed from the end(s), not only just a group of characters (does the equivalent of .startswith and .endswith).
What was the outcome? Use the X-line function that can be defined as Y. I'll stick with "use re".
- Josiah
participants (2)
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Calvin Spealman -
Josiah Carlson