CODEWITHSUNDEEP
ruby-on-railsrubyregex
silent
silent

Reputation: 4004

How do I replace a group of reserved chars into " " in Ruby on Rails?

I want to replace the following reserved chars into spaces:

+ - & | ! ( ) { } [ ] ^ " ~ * ? : \

This is my code, but it doesn't work. Did I miss anything?

keyword = keyword.gsub(/\\+-&\\|!\\(\\)\\{\\}\\[\\]\\^"~\\*\\?:\\\\/, ' ')

Upvotes: 4

Views: 1349

Answers (4)

the Tin Man
the Tin Man

Reputation: 160551

Here's a benchmark showing the speed difference between gsub and tr:

require 'benchmark'
require 'pp'

STR = '+ - & | ! ( ) { } [ ] ^ " ~ * ? : \\'
LONG_STR = STR * 1_000
N = 1_000

puts `ruby -v`

pp STR.gsub(/[+&|!(){}\[\]^"~*:?\\-]/, ' ')
pp STR.tr('-+&|!(){}[]^"~*?:\\', ' ')

Benchmark.bm(5) do |b|
  b.report('gsub') { N.times { LONG_STR.gsub(/[+&|!(){}\[\]^"~*:?\\-]/, ' ') } }
  b.report('tr') { N.times { LONG_STR.tr('+&|!(){}[]^"~*:?\\-', ' ') } }
end

And the output:

ruby 1.8.7 (2012-02-08 patchlevel 358) [universal-darwin12.0]
"                                   "
"                                   "
          user     system      total        real
gsub  13.300000   0.190000  13.490000 ( 13.524779)
tr     0.080000   0.010000   0.090000 (  0.090045)

ruby 1.9.3p392 (2013-02-22 revision 39386) [x86_64-darwin12.2.0]
"                                   "
"                                   "
            user     system      total        real
gsub   17.890000   0.040000  17.930000 ( 18.016657)
tr      0.270000   0.000000   0.270000 (  0.283021)

ruby 2.0.0p0 (2013-02-24 revision 39474) [x86_64-darwin12.2.0]
"                                   "
"                                   "
            user     system      total        real
gsub    7.310000   0.020000   7.330000 (  7.361403)
tr      0.140000   0.010000   0.150000 (  0.145816)

It's interesting that 1.8.7 out-performed 1.9.3. I suspect it's because of the addition of multibyte character support in 1.9+.

I've done several benchmarks with 2.0 and have been very happy with the speed improvements I've seen.

Upvotes: 10

pguardiario
pguardiario

Reputation: 54984

This is what tr is for:

keyword.tr '-+&|!(){}[]^"~*?:\\', " "
#=> "                                   "

Upvotes: 10

shweta
shweta

Reputation: 8169

\W = Any non-word character

>> keyword = '+ - & | ! ( ) { } [ ] ^ " ~ * ? : \\'
=> "+ - & | ! ( ) { } [ ] ^ \" ~ * ? : \\"
>> keyword.gsub!(/\W/," ")
=> "                                   "

Upvotes: 0

Peter
Peter

Reputation: 132197

Just do this.

keyword.gsub!(/[+\-&|!(){}\[\]^"~*?:\\]/, " ")

Check:

>> keyword = '+ - & | ! ( ) { } [ ] ^ " ~ * ? : \\'
=> "+ - & | ! ( ) { } [ ] ^ \" ~ * ? : \\"
>> keyword.gsub!(/[+\-&|!(){}\[\]^"~*?:\\]/, " ")
=> "                                   "

Character classes (enclosed by []) are easier to reason about in this case. You need to escape - and [ and ] and \.

Upvotes: 4

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