Too greedy of a regexp

ruby-talk
1

i have a regexp: /(^BillHead(.*))(^Bill_End(.*))/m that's too greedy for
processing
a billing extract file containing:
BillHead...<<<much information here>>\n
<<one or more detail lines here\n>>
Bill_End...<<<much information here>>\n
BillHead...<<<much information here>>\n
<<one or more detail lines here\n>>
Bill_End...<<<much information here>>\n
...etc.... to EOF....

..i get the whole file matched....i just want each invoice...
it will eventually be in a oneliner like
a=File.read("billfile").scan(regexp)

so what is the non-greedy way for the above regexp to properly match
each invoice...

···

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2

try:

/(^BillHead(.*?))(^Bill_End(.*?))\n/m

or

/(^BillHead(.*?))(^Bill_End([^\n].*))\n/m

notice the .*? instead of .*

.*? has some pecularities, that were discussed here some time ago, so
perhaps you'd want to find them in the archives. (search for 'greedy'
or 'regex' - I don't remeber now)

···

On 11/9/06, Dave Rose <bitdoger2@yahoo.com> wrote:

i have a regexp: /(^BillHead(.*))(^Bill_End(.*))/m that's too greedy for
processing
a billing extract file containing:
BillHead...<<<much information here>>\n
<<one or more detail lines here\n>>
Bill_End...<<<much information here>>\n
BillHead...<<<much information here>>\n
<<one or more detail lines here\n>>
Bill_End...<<<much information here>>\n
...etc.... to EOF....

..i get the whole file matched....i just want each invoice...
it will eventually be in a oneliner like
a=File.read("billfile").scan(regexp)

so what is the non-greedy way for the above regexp to properly match
each invoice...

3

Jan Svitok wrote:

i have a regexp: /(^BillHead(.*))(^Bill_End(.*))/m that's too greedy for
processing
a billing extract file containing:
BillHead...<<<much information here>>\n
<<one or more detail lines here\n>>
Bill_End...<<<much information here>>\n
BillHead...<<<much information here>>\n
<<one or more detail lines here\n>>
Bill_End...<<<much information here>>\n
...etc.... to EOF....

..i get the whole file matched....i just want each invoice...
it will eventually be in a oneliner like
a=File.read("billfile").scan(regexp)

so what is the non-greedy way for the above regexp to properly match
each invoice...

try:

/(^BillHead(.*?))(^Bill_End(.*?))\n/m

or

/(^BillHead(.*?))(^Bill_End([^\n].*))\n/m

notice the .*? instead of .*

*? has some pecularities, that were discussed here some time ago, so
perhaps you'd want to find them in the archives. (search for 'greedy'
or 'regex' - I don't remeber now)

I would also remove the last .* because that likely eats up the rest of the document. So that would be

/^BillHead(.*?)^BillEnd/m

Another approach is to do

s.split(/^(Bill(?:Head|End))/m)

and then go through the array.

irb(main):006:0> "BillHead\nfoo\nbar\nBillEnd".split(/^(Bill(?:Head|End))/m)
=> ["", "BillHead", "\nfoo\nbar\n", "BillEnd"]

Kind regards

  robert

···

On 11/9/06, Dave Rose <bitdoger2@yahoo.com> wrote:

4

Robert Klemme wrote:

Jan Svitok wrote:

...etc.... to EOF....

/(^BillHead(.*?))(^Bill_End(.*?))\n/m

or

/(^BillHead(.*?))(^Bill_End([^\n].*))\n/m

notice the .*? instead of .*

=> ["", "BillHead", "\nfoo\nbar\n", "BillEnd"]

Kind regards

  robert

i played around in irb with a shorten extract file and found that:
b=File.read("drbilp.txt").scan(/(^BillHead(.*?))(^Bill_End(\d*)(\s*UBPBILP1\n)(.*?))/m)
works in that separates each invoice in an sub-array of size=6
in which b[0]+b[2] completes that task of reading,scanning
correctly
and puting all in a ruby 'container' that i can do an each on....thanx
dave

···

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