\s in regex

[s moon]

what I want is to remove beginning and trailing spaces from lines.

this is a failed try.

ifile.each { | line |
ofile.print line.sub(/^\s+/,"").sub(/\s+$/,"")
}

this removes spaces from begin and end of lines
but it also removes blank lines.
it seems \s matches \r or \n also.


this is another one, this time it works.

ifile.each { | line |
if line =~ /^\s*$/ # take care of blank lines
ofile.print line
else
ofile.print line.sub(/^\s+/,"").sub(/\s+$/,"")
end
}

but can i do this with one line without if-then-else?

thanks

 

[Mike Stok]

what I want is to remove beginning and trailing spaces from lines.

this is a failed try.

ifile.each { | line |
ofile.print line.sub(/^\s+/,"").sub(/\s+$/,"")
}

this removes spaces from begin and end of lines
but it also removes blank lines.
it seems \s matches \r or \n also.

One approach might be to use String#strip as suggested by another
poster, and to use IO#puts to supply the line ending e.g.

ifile.each { |line|
ofile.puts line.strip
}

This is "quick and dirty" and will add a \n to the last line from the
input even if there wasn't a final \n in the inpyt stream.

Hope this helps,

Mike

 

[ahoward]

On Fri, 27 Jun 2003, s moon wrote:

/usr/home/howardat/eg/ruby > cat blank.rb
#!/usr/bin/env ruby

re = %r/^\s*(.*?)\s*$/o

DATA.each do |line|
p re.match(line).to_a
end

__END__
zero zero
one one one

three

five


/usr/home/howardat/eg/ruby > ruby blank.rb
[" zero zero\t ", "zero zero"]
[" one\t one one ", "one\t one one"]
["", ""]
[" three ", "three"]
["", ""]
[" five\t", "five"]

-a
--
====================================
| Ara Howard
| NOAA Forecast Systems Laboratory
| Information and Technology Services
| Data Systems Group
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| ~ > ruby -e 'p(%.\x2d\x29..intern)'
====================================

 

[Brian Candler]

what I want is to remove beginning and trailing spaces from lines.
A blank line will be seen as "\n" in your example, and yes it is eaten by \s:

irb(main):001:0> "\n".sub(/^\s+/,"")
=> ""

But it's not eaten at the other end, since $ doesn't match the end of
string, it matches before the newline:

irb(main):002:0> "\n".sub(/\s+$/,"")
=> "\n"

So you can solve it like this:

line.sub(/^\s*(.*?)\s*$/,'\1')

where .*? means "match any character any number of times, but eat as few
characters as possible whilst still allowing the whole regexp to match"

Or else, as others have mentioned, just remove it anyway (String#strip does
this) and add a "\n" back again.

Regards,

Brian.

 

[Mauricio Fernández]

| ~ > ruby -e 'p(%.\x2d\x29..intern)'

batsman@tux-chan:~$ ruby -v
ruby 1.8.0 (2003-03-03) [i686-linux]
batsman@tux-chan:~$ ruby -e 'p(%.\x2d\x29..intern)'
:"-)"
batsman@tux-chan:~$ /usr/bin/ruby -v
ruby 1.6.8 (2002-12-24) [i386-linux]
batsman@tux-chan:~$ /usr/bin/ruby -e 'p(%.\x2d\x29..intern)'

batsman@tux-chan:~$ ruby -e 'p ")".intern'
:")"
batsman@tux-chan:~$ /usr/bin/ruby -e 'p ")".intern'


Beware


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