Two dimensional regexp matching?

[Donald McCarthy]

I feel so stupid after David Goodger pointed out that I should match 
over multiple lines.
Of course!

So, my example search becomes:
    r"([DG]).\n(?:..\n){0,2}.W\n(?!.\1\n)"

Or, more clearly:
    r'''(?x)# Verbose
   #point1        point2                   # Comment
    ([DG])        .        \n              # point1 == (D or G)
    (?:.          .        \n){0,2}        # within three samples
    .             W        \n              # THEN point2 == W
    (?!.          \1       \n)             # next point2 != earlier point1
    '''

Well, time to try it.

Thanks.


Paddy wrote:

> We already have the re module for regular expression matching on a 
> string.
>
> I am looking for pointers to references/algorithms for regular 
> expression matching for
> files of tabular data, i.e.
>
>     Table definition
>     ================
>     1) Samples from one point in the system appears in a column of the 
> table.
>     2) Samples encoded as characters
>     3) All points in the system are sampled at the same time to 
> produce successive
>        rows of the table
>
> So a system sampled at two points in successively may produce the 
> following file:
>
>     GH
>     DF
>     AS
>     QW
>     FF
>     SD
>
> I want to be able to do regular expression type searches within the 
> file. Things like
>  Where can I find point1 == (D or G) then point2 == W within three 
> samples and where the
> next sample of point2 != the earlier sample of point1?
>
> That was a small example, in reality there is usually hundreds of 
> points and tens of
> thousands of samples in multi-megabyte files but I'd first like to see 
> if anyone else has
> considered this kind of 'two dimensional regexp matching'
>
> Note: I DO NOT have queries in the date on sample points. The queries 
> will always be "Find
> the range of sample times in which 'this' occurs".
>
> U have tried Google but without success - I don't know enough to think 
> of a suitable
> search phrase, or, (much less likely), Google doesn't have it ;-)
>
>
> Thanks in advance, Paddy.
>