validate string is valid maths

[Matthew_WARREN at bnpparibas.com]

Hi pythoners.

I am generating strings of length n, randomly from the symbols

+-/*0123456789

What would be the 'sensible' way of transforming the string, for example
changing '3++++++8' into 3+8
or '3++--*-9' into '3+-9' such that  eval(string) will always return a
number?

in cases where multiple symbols conflict in meaning (as '3++--*-9' the
earliest valid symbols in the sequence should be preserved

so for example,

'3++*/-9'         =     3+-9
'45--/**/+7'      =     45-+7
'55/-**+-6**'     =     55/-6

...that is, unless there is a canonical method for doing this that does
something else instead..


this sounds like homework. It's not. I like making problems up and it's a
slow work day. So, as an aside, there is no real reason I want to do this,
nor other problem to solve, nor other background to what I'm trying to
achieve ;) other than twiddling with python.

Matt.



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