Why am I getting this string error?

Can someone explain to me why I’m getting the error below for this part
of a script? It doesn’t seem to like line 24, the scan line, but, I’ve
got this same code being used for other needs and it doesn’t complain at
all there.

Thanks,
Peter


20 Dir.glob(".ps").each do |psfile|
21 $filetime = File.ctime(psfile)
22 $filetime = $filetime.to_s.gsub!(/ -.
$/, “”)
23 file_contents = File.read(psfile)
24 file_contents.scan(/%%Pages: (\d{1,5})[ ]+\n/) do
25 totalpages = $1
26 if (totalpages.to_i % 2) !=0 then
27 totalpages = totalpages.to_i + 1
28 file_contents << “%%Blank page for Asura.\n%%Page:
29 #{totalpages.to_i}\nshowpage\n”
30 File.open(psfile, “w”) { |f| f.print file_contents }
31 FileUtils.touch(psfile)
32 end

getting this error:

rubyw indexpagecounts_6x9.rbw
indexpagecounts_6x9.rbw:24:in scan': string modified (RuntimeError) from indexpagecounts_6x9.rbw:24 from indexpagecounts_6x9.rbw:20:ineach’
from indexpagecounts_6x9.rbw:20
Exit code: 1

Peter B. wrote:

Can someone explain to me why I’m getting the error below for this part
of a script? It doesn’t seem to like line 24, the scan line, but, I’ve
got this same code being used for other needs and it doesn’t complain at
all there.

from indexpagecounts_6x9.rbw:24
from indexpagecounts_6x9.rbw:20:in `each’
from indexpagecounts_6x9.rbw:20

Exit code: 1

You’re modifying file_contents during scan, so scan gets confused.
from what I see, you’d better use gsub! with a block, since, if I
understood your point, you are basically inserting text where you detect
something.

Vince


20 Dir.glob(".ps").each do |psfile|
21 $filetime = File.ctime(psfile)
22 $filetime = $filetime.to_s.gsub!(/ -.
$/, “”)
23 file_contents = File.read(psfile)
24 file_contents.scan(/%%Pages: (\d{1,5})[ ]+\n/) do
25 totalpages = $1
26 if (totalpages.to_i % 2) !=0 then
27 totalpages = totalpages.to_i + 1
28 file_contents. << “%%Blank page for Asura.\n%%Page:
29 #{totalpages.to_i}\nshowpage\n”
30 File.open(psfile, “w”) { |f| f.print file_contents }
31 FileUtils.touch(psfile)
32 end

You’re modifying file_contents during scan, so scan gets confused.
from what I see, you’d better use gsub! with a block, since, if I
understood your point, you are basically inserting text where you detect
something.

Vince

Thanks, Vince. I see what you mean, and, I did change it to use a gsub!.
I’ve always thought of gsub as a changer for little things, not huge
files like this, but, it works fine. Thanks again.

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