[Tutor] finding sum of digits in a string

[Dennis Lee Bieber]

On Tue, 15 Mar 2022 09:53:58 +1100, Cameron Simpson <cs at cskk.id.au>
declaimed the following:


>>
>>1) sum(int(ele) for ele in st if ele in "123456789")
>>

>And, in fact, your own code there _is_ incorrect, technically, though I 
>suppose that adding "0" has no effect, so missing it out in the string 
>still produces a correct result.
>
	I'd missed that on my first glance at the code (and I should note that
I've sort of started ignoring the OP -- 99% of their posts come down to
some trivial example that is highly unlikely to be seen in any actual
program, and the "question" is one of aesthetics/style, which is highly
subjective to the experience of the reader).

	However, based upon https://docs.python.org/3/library/string.html, the
first version could be replaced with

	import string

	sum(int(ele) for ele in st if ele in string.digits)

>>> import string
>>> string.digits
'0123456789'

That avoids the "missing" digit ambiguity/error, along with the overhead of
call ele.isdigit() for each character in the input (after all, .isdigit()
probably does a loop over each character in "ele" and does the same "in
string.digits" test internally)



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	Wulfraed                 Dennis Lee Bieber         AF6VN
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