Re^2: accessing specific data in a file

Hi Guys, thanks heaps for all your replies. that helped me understand more of reg exp in perl, but I'm not quite there yet :(
Graff, you're right in saying the sample has a lot of whitespaces. I copied and pasted the format as is. so the while loop looks like it's the way to go. the Coordinate field in vrml has thousands of those points where each set of 3 represents (x,y,z) coordinates. A snippet of the code looks like

        geometry IndexedFaceSet {
            coord
            Coordinate {
                point [  265.185 -166.225 -510.375,
                     264.529 -166.901 -513.43,
                     269.321 -166.425 -510.918,
                     271.021 -166.956 -513.279,
                     271.223 -167.21 -514.637,
                     272.77 -166.984 -514.019,
                     270.767 -167.555 -516.859,
                     268.668 -167.344 -515.143,
                     272.884 -167.285 -515.945,
                     266.267 -167.539 -516.835,
                     267.193 -167.766 -518.544,
                     272.686 -167.438 -517.418,
                     269.214 -167.83 -519.399,
                     274.761 -166.996 -515.928,
                     275.801 -166.946 -519.035,
                     264.372 -167.451 -517.076,
                     266.21 -167.785 -519.148,
                     263.801 -167.367 -516.587,
                     269.266 -167.919 -521.463,
                     271.322 -167.821 -522.477,
                     266.656 -168.197 -528.597,
                     269.644 -168.342 -527.906,
                     267.007 -167.981 -524.961,
                     264.07 -167.493 -517.639,
                     263.244 -167.65 -520.707,
                     267.726 -167.91 -521.09,
                     264.468 -167.739 -523.493]
                  }
[download]

This would give the coordinates for points defining one block.
The model has a number (around 30) of blocks within it, each with a Coordinate field. and I need to read all the points from all the blocks. I tried playing around with the few suggestions provided, but still does not have to right reg exp to match the format I am seeking. what does colon (:) mean in ((?:\s*\d+){3}) I tried something like


while ( $array =~ /\[         #open sq bracket
    ((?:\s*\d+){3})       #match 3 numerics
    ,
    ((?:\s*\d+){3})
    \]
    /gx)
{
    print "Grr: get inside this loop";
}
[download]

on a test sample where there were only 2 sets of (x,y,z) coordinates within sq brackets. the print statement is not getting executed. thanks again for your precious help!!:) Phoenix.

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Re^3: accessing specific data in a file by graff (Chancellor) on Mar 26, 2006 at 19:20 UTC
Okay -- the data sample in the OP had only integer values, so I didn't try to accommodate decimal points or minus signs. To handle that, just expand a bit on "\d" in the regex: `/\[ #open sq bracket ((?:\s[-.\d]+){3}) #match 3 numerics, incl. decimal point and/o +r minus sign , ((?:\s[-.\d]+){3}) \] /gx` [download] The square brackets (not escaped by backslash) define a character class, consisting of the dash, the period and any digit. Note that the dash needs to be first or last inside the brackets in order to be treated as a literal dash; if it were in the middle between to other characters, it would define a range of characters (e.g. <code> a-z </code which matches all lower-case letters). You can definitely benefit from reading the perlre and perlretut man pages. Please do that. update: Actually, looking at your more detailed data sample, it looks like the regex given above won't work -- there are a lot more sets of numerics between a given pair of square brackets. I'm afraid I don't understand how that many sets of values can constitute a single "Coordinate". If you need more help, you first need to be more clear about how the data are supposed to be interpreted, and what you really intend to do with the sets of values that are given to you that way.	[reply] [d/l]

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Re^3: accessing specific data in a file
by graff (Chancellor) on Mar 26, 2006 at 19:20 UTC

    /\[         #open sq bracket
    ((?:\s*[-.\d]+){3})   #match 3 numerics, incl. decimal point and/o
+r minus sign
    ,
    ((?:\s*[-.\d]+){3})
    \]
    /gx
[download]

a-z

You can definitely benefit from reading the perlre and perlretut man pages. Please do that.

update: Actually, looking at your more detailed data sample, it looks like the regex given above won't work -- there are a lot more sets of numerics between a given pair of square brackets. I'm afraid I don't understand how that many sets of values can constitute a single "Coordinate". If you need more help, you first need to be more clear about how the data are supposed to be interpreted, and what you really intend to do with the sets of values that are given to you that way.

[reply]
[d/l]