[Edu-sig] zip

Arthur ajsiegel at optonline.net
Mon Dec 15 09:37:22 EST 2003

>Ain't 'zip' cool.

>The problem that zip addresses occurred over and over in my code.

(To Guido's chagrin) I do become fascinated and interested in language
design issues.

'zip', for my purposes, was perfect.  The intention, in my cases, is to
iterate over lists of equal lengths.  But there are corner cases in which
the len of the lists become unequal, and I needed to test and adjust for
that.  My adjustment was exactly what zip provides - what the heck, go over
the shorter of the two lists. Good enough for my purposes. Actually helped
bulletproof my code.  But only because there are parts of my code (when I'm
just drawing, after all) where good enough is good enough. That is often not
the case when programming. 

So as much as I appreciate 'zip' I recognize danger in it, because an
unequal length list condition might also indicate an unexpected 'out of
balance' condition as well as an expected one. That condition was more
likely to be exposed with the 'old fashioned' way of handling the situation
which zip addresses. So, in using zip, without some caution, an unexpected
condition - a bug -  might pass silently.

The edu-sig relevance, I guess, is that there are always trade-offs, and
therefore subtleties every way one turns. And, in the end, often no way to
make things truly 'simple'.

And students of the language, IMO, need to understand that upfront. And to
take responsibility in all cases.  It's all in the docs.

But the reality is that probably the only way one is going to get one's arms
fully around something as simple as the full implications of 'zip' is to get
bitten by it once.  Or at least that's how I end up learning most of the
nooks and crannies.

Having been bitten enough times and taken it like a .. (be careful)
programmer, I sort of expect others to do the same.

And get cranky when they don't. Which has been the base source of some of my
crankiness when the issue of "newbies" and Python's responsibilities to them
comes up again and again.


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