[Tutor] string to list
Eike Welk
eike.welk at gmx.net
Wed Feb 10 15:24:46 CET 2010
On Wednesday February 10 2010 14:32:52 Owain Clarke wrote:
> My son was doing a statistics project in which he had to sort some data by
> either one of two sets of numbers, representing armspan and height of a
> group of children - a boring and painstaking job. I came across this
> piece of code:-
>
> li=[[2,6],[1,3],[5,4]] # would also work with li=[(2,6),(1,3),(5,4)]
> li.sort(key=lambda x:x[1] )
> print li
>
> It occurred to me that I could adapt this so that he could input his data
> at the command line and then sort by x:x[0] or x:x[1]. And I have not
> discovered a way of inputting a list, only strings or various number
> types.
I would let him enter the data into the program text directly, or parse a text
file with a simple format. Something like:
in_data = [
#arm span, height
[2 , 6 ],
[1 , 3 ],
[5 , 4 ],
[ , ],
[ , ],
[ , ],
]
This way the computation can be repeated when there were errors int the data.
Otherwise one error might spoil all the work he did while typing in the data.
Designing a simple text representation of the data and interpreting it with a
computer program, is much more easy that writing good user interfaces.
For the same reason Unix, a concept from the late 1960s, is still doing
relatively well.
Eike.
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