Why doesn't Python 2.6 have set literals and comprehensions or dict comprehensions? [closed]
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19-08-2019 - |
Question
Python 2.6 was basically a stepping stone to make converting to Python 3 easier. A lot of the features destined for Python 3 were implemented in 2.6 if they didn't break backward compatibility with syntax and the class libs.
Why weren't set literals ({1, 2, 3}
), set comprehensions ({v for v in l}
), or dict comprehensions ({k: v for k, v in d}
) among them? In particular dict comprehensions would have been a great boon... I find myself using the considerably uglier dict([(k, v) for k, v in d])
an awful lot lately.
Is there something obvious I'm missing, or was this just a feature that didn't make the cut?
Solution
It wasn't done because nobody took the time to do it. There are bugs opened for months, and no one commented on them:
So it wasn't important enough for anybody to care, probably.
OTHER TIPS
All these are syntax/grammar changes. Such changes are traditionally introduced first in a Python x.y version with a from __future__ import …
statement, and implemented at least on Python x.(y+1) version. Such a transition hasn't happened yet for these changes.
Technically, I've answered your "why".
Now, if you meant, “why didn't anyone take the time to suggest, support and implement something that I would like to have in 2.x also, even if they don't know about it since I never tried to suggest/support backporting those syntax enhancements in either comp.lang.python or Python-Dev and I never tried to even read the PEPs?”, then the answer lies in you too, and you can offer an answer yourself.
HTH
BTW, you shouldn't use the dict([(k,v) for k,v in d])
form, but the dict((k,v) for k,v in d)
. More efficient. Why create an intermediate list?