There's something macho about programmers when it comes to regular expressions - so often they'll try and do the whole job in a single regular expression when doing a two stage process is much more logical, much quicker in operation, and far easier to code.
Take a requirement that came up this morning, for example, to extract data from a netlist. The data to be handled might look like:
[5560] = !V5*V6*V7*!V8 + [5223]
and the requirement is to return a list elements separated by = or + signs, and then to return a list of nodes or inputs within those elements. In other words, what's wanted is:
['5560']
['!V5', 'V6', 'V7', '!V8']
['5223']
I think I have rather made my point already by how I described the requirement, haven't I? Two regular expressions ...
I'm running a
Python course, so the example's in Python ...
full source code and
more Python regular expression examples available!
(written 2006-04-05, updated 2006-06-05)
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