scanf in python

[Diez B. Roggisch]

AMD schrieb:
> Hello,
> 
> I often need to parse strings which contain a mix of characters, 
> integers and floats, the C-language scanf function is very practical for 
> this purpose.
> I've been looking for such a feature and I have been quite surprised to 
> find that it has been discussed as far back as 2001 but never 
> implemented. The recommended approach seems to be to use split and then 
> atoi or atof or to use regex and then atoi and atof. Both approaches 
> seem to be a lot less natural and much more cumbersome than scanf. If 
> python already has a % string operator that behaves like printf, why not 
> implement either a %% or << string operator to behave like scanf, use 
> could be like the followng:
> 
> a, b, c = "%d %f %5c" %% "1 2.0 abcde"
> 
> or
> 
> a, b, c = "%d %f %5c" << "1 2.0 abcde"
> 
> %% is closer to the % operator
> 
> << seems more intuitive to me
> 
> either of this methods seems to me much simpler than:
> 
> lst = "1 2;0 abcde".split()
> a = int(lst[0])
> b = float(lst[1])
> c = lst[2]
> 
> or even worse when using regular expressions to parse such simple input.
> 
> I like python because it is concise and easy to read and I really think 
> it could use such an operator.
> 
> I know this has been discussed before and many times, but all previous 
> threads I found seem to be dead and I would like to invite further 
> investigation of this topic.

I'm pretty certain python won't grow an additional operator for this. 
Yet you are free to create a scanf-implementation as 3rd-party-module.

IMHO the usability of the approach is very limited though. First of all, 
the need to capture more than one input token is *very* seldom - nearly 
all commandline-tools I know that do require interactive user-input 
(like the linux kernel config tool) do so by providing either 
line-by-line value entry (including defaults, something you can't do 
with your approach), or even dialog-centric value entry with curses.

So - I doubt you will gather much momentum on this. Good luck though.


Diez