Regex \s == \n?


#1

I’m trying to remove extra spaces from a long string which has some
EOLs, using regex. It’s not working. Here’s a simple demo:

irb(main):004:0> a="\n abc\n a a a"
=> “\n abc\n a a a”
irb(main):005:0> a.gsub(/\s+/,’ ')
=> " abc a a a"

I’ve dug around in my regex references, and all I can say is that is
hasn’t been the least bit helpful. I’m probably not looking for the
right thing.

Can someone more knowledgeable tell me is there’s a way to do this -
remove extra spaces without removing the EOLs?

Thanks!

t.

Tom C., MS MA, LMHC - Private practice Psychotherapist
Bellingham, Washington, U.S.A: (360) 920-1226
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#2

Alle Friday 06 February 2009, Tom C. ha scritto:

right thing.

Can someone more knowledgeable tell me is there’s a way to do this -
remove extra spaces without removing the EOLs?

Thanks!

t.

According to “The Ruby P.ming Language”, \s is equivalent to "
\t\n\r\f".
So, if you want avoid removing newlines, you’ll need to replace \s with
[ \t\r\f] or with a whitespace if you’re only intersted in it:

a="\n abc\n a a a"
a.gsub(/ +/, ’ ')
=>"\n abc\n a a a"

I hope this helps

Stefano


#3

Tom,

If you’re just speaking of the space character and you want to replace
double-spaces (or triple-spaces or more) with just a single space, you
can
do this.

puts a.gsub(/ +/," ")

Joe


#4

Stefano, Joe - thank you! I’m only just getting into regex, so I get
easily lost. You solved my problem - each in different ways. A lot of
bang for the buck, indeed!

t.

joe chesak wrote:

On Fri, Feb 6, 2009 at 1:10 PM, Tom C. removed_email_address@domain.invalid wrote:

I’ve dug around in my regex references, and all I can say is that is hasn’t

Tom C., MS MA, LMHC - Private practice Psychotherapist
Bellingham, Washington, U.S.A: (360) 920-1226
<< removed_email_address@domain.invalid >> (email)
<< TomCloyd.com >> (website)
<< sleightmind.wordpress.com >> (mental health weblog)

#5

On Feb 6, 7:10 am, Tom C. removed_email_address@domain.invalid wrote:

right thing.
A newline is a whitespace char. \s is the same as [ \t\r\n\f]. If you
don’t want to match them, remove them. Try
a.gsub(/[ \t]+/,’ ')

–Mark


#6

Hi –

On Fri, 6 Feb 2009, Tom C. wrote:

Stefano, Joe - thank you! I’m only just getting into regex, so I get easily
lost. You solved my problem - each in different ways. A lot of bang for the
buck, indeed!

Another variant:

a.gsub(/[^\S\n]+/, " ")

That character class means “all characters that are not a non-space or
\n.” (The ^ is the “not” part.)

You might also be able to use squeeze:

p “abc def \n ghi\n”.squeeze # “abc def \n ghi\n”

though that’s going to be less versatile if you’re dealing, say, with
tabs.

David


David A. Black / Ruby Power and Light, LLC
Ruby/Rails consulting & training: http://www.rubypal.com
Coming in 2009: The Well-Grounded Rubyist (http://manning.com/black2)

http://www.wishsight.com => Independent, social wishlist management!


#7

On Feb 6, 9:37 am, Julian L. removed_email_address@domain.invalid wrote:

Can’t you use squeeze?

Best idea yet. Might as well use a built-in, rather than reinventing
one.

a.squeeze(" ")

Thanks for the reminder. I should review String#instance_methods every
once in a while. There’s some good stuff there.


#8

Can’t you use squeeze?

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#9

David A. Black wrote:

Hi –

(squeeze defaults to " " as its argument, so you don’t have to provide
an argument unless it’s something different.)

David

Is that a 1.9.1 change? In 1.8.6 String#squeeze squeezes everything if
no arguments are given.

"abc aabbcc ".squeeze
#=>"abc abc "

Siep


#10

Hi –

On Sat, 7 Feb 2009, Mark T. wrote:

On Feb 6, 9:37Â am, Julian L. removed_email_address@domain.invalid wrote:

Can’t you use squeeze?

Best idea yet. Might as well use a built-in, rather than reinventing
one.

a.squeeze(" ")

See my earlier post in this thread. squeeze is a good candidate as
long as you don’t mind preserving all non-" " whitespace, including
tabs.

(squeeze defaults to " " as its argument, so you don’t have to provide
an argument unless it’s something different.)

David


David A. Black / Ruby Power and Light, LLC
Ruby/Rails consulting & training: http://www.rubypal.com
Coming in 2009: The Well-Grounded Rubyist (http://manning.com/black2)

http://www.wishsight.com => Independent, social wishlist management!


#11

David A. Black wrote:

a.gsub(/[^\S\n]+/, " ")

David

Thanks, David. I continue to be amazed by the depth of your knowledge,
and outright cleverness. In pursuing this simply problem I’m
inadvertently learning a lot. I’m grateful. Thanks for your contribution
that process!

t.

Tom C., MS MA, LMHC - Private practice Psychotherapist
Bellingham, Washington, U.S.A: (360) 920-1226
<< removed_email_address@domain.invalid >> (email)
<< TomCloyd.com >> (website)
<< sleightmind.wordpress.com >> (mental health weblog)

#12

Hi –

On Sat, 7 Feb 2009, Siep K. wrote:

no arguments are given.

"abc aabbcc ".squeeze
#=>"abc abc "

Sorry, my mistake. It does squeeze everything.

David


David A. Black / Ruby Power and Light, LLC
Ruby/Rails consulting & training: http://www.rubypal.com
Coming in 2009: The Well-Grounded Rubyist (http://manning.com/black2)

http://www.wishsight.com => Independent, social wishlist management!


#13

Sorry, forgot the " " argument

Blog: http://random8.zenunit.com/
Learn rails: http://sensei.zenunit.com/