Regexp help : RUBY

K, so I suck at regular expressions. I just don't seem to understand
them.

What I want to do is determine if a string includes 2 special characters
a semi-colon and a question mark.

Here's my example that I'm trying to work with.

irb(main):009:0> encoding = ";6277200301500269=?"
=> ";6277200301500269=?"
irb(main):010:0> encoding.include?(%r{;\?}.to_s)
=> false
irb(main):011:0>

I want this to return true, but it doesn't


Can anyone help me out?


thanks,

~Jeremy
--
Posted via http://www.ruby-forum.com/.

Jeremy Woertink wrote:
> What I want to do is determine if a string includes 2 special characters
> a semi-colon and a question mark.

You don't need regular expressions to do that, try this instead:

irb> encoding.include? ";" and encoding.include? "?"
=> true

On the other hand, if you want to use regular expressions regardless,
you should notice that String#include? takes a string rather than a
Regexp.

Note that:
irb> %r{;\?}.to_s
> "(?-mix:;\\?)"

So
encoding.include?(%r{;\?}.to_s)

is equivalent to
encoding.include?("(?-mix:;\\?)")

which is not going to succeed.

To use a regexp, try:
irb> encoding =~ /(;.*\?)|(\?.*/
=> true.

best
Dan
--
Posted via http://www.ruby-forum.com/.

Daniel Lucraft wrote:
> Jeremy Woertink wrote:
>> What I want to do is determine if a string includes 2 special characters
>> a semi-colon and a question mark.
>
> You don't need regular expressions to do that, try this instead:
>
> irb> encoding.include? ";" and encoding.include? "?"
> => true
>
> On the other hand, if you want to use regular expressions regardless,
> you should notice that String#include? takes a string rather than a
> Regexp.
>
> Note that:
> irb> %r{;\?}.to_s
> > "(?-mix:;\\?)"
>
> So
> encoding.include?(%r{;\?}.to_s)
>
> is equivalent to
> encoding.include?("(?-mix:;\\?)")
>
> which is not going to succeed.
>
> To use a regexp, try:
> irb> encoding =~ /(;.*\?)|(\?.*/
> => true.
>
> best
> Dan

Thanks for the help. I would like to use a regexp becuase I think it
will look nicer in the code. I tried your example and got

C:\rails_apps\hotswipe>irb
irb(main):001:0> require 'config/environment'
=> true
irb(main):002:0> encoding = ";6277200301500269=?"
=> ";6277200301500269=?"
irb(main):003:0> encoding =~ /(;.*\?)|(\?.*/
=> 0
irb(main):004:0>

So what does the 0 mean? 0 matches? If all else fails, I will use the
ugly version


thanks,
~Jeremy
--
Posted via http://www.ruby-forum.com/.

On Sep 18, 4:04 pm, Jeremy Woertink <jeremywoert...@gmail.com> wrote:
> Daniel Lucraft wrote:
> > Jeremy Woertink wrote:
> >> What I want to do is determine if a string includes 2 special characters
> >> a semi-colon and a question mark.
>
> > You don't need regular expressions to do that, try this instead:
>
> > irb> encoding.include? ";" and encoding.include? "?"
> > => true
>
> > On the other hand, if you want to use regular expressions regardless,
> > you should notice that String#include? takes a string rather than a
> > Regexp.
>
> > Note that:
> > irb> %r{;\?}.to_s
> > > "(?-mix:;\\?)"
>
> > So
> > encoding.include?(%r{;\?}.to_s)
>
> > is equivalent to
> > encoding.include?("(?-mix:;\\?)")
>
> > which is not going to succeed.
>
> > To use a regexp, try:
> > irb> encoding =~ /(;.*\?)|(\?.*/
> > => true.
>
> > best
> > Dan
>
> Thanks for the help. I would like to use a regexp becuase I think it
> will look nicer in the code. I tried your example and got
>
> C:\rails_apps\hotswipe>irb
> irb(main):001:0> require 'config/environment'
> => true
> irb(main):002:0> encoding = ";6277200301500269=?"
> => ";6277200301500269=?"
> irb(main):003:0> encoding =~ /(;.*\?)|(\?.*/
> => 0
> irb(main):004:0>
>
> So what does the 0 mean? 0 matches? If all else fails, I will use the
> ugly version

It means that it found the first match starting at index 0 in the
string. (Try reading the documentation on the =~ method.)

Note that the supplied regexp will fail if your string has a newline
in it. You may want to append the 'm' (multiline) modifier to it, e.g.
/;.*\?|\?.*;/m
(There's also no need for the parentheses, and a minor theoretical
speed/memory reason to leave them off.)

Gavin Kistner wrote:
> It means that it found the first match starting at index 0 in the
> string. (Try reading the documentation on the =~ method.)
>

ok, that makes sense. I did check out the docs on
http://www.ruby-doc.org/core/
I clicked the =~ method under Regexp and it sends me to
rxp.match(str) => matchdata or nil
Returns a MatchData object describing the match, or nil if there was no
match. This is equivalent to retrieving the value of the special
variable $~ following a normal match.

which didn't say anything about indexes. Are there any other sites that
have different documentation?


~Jeremy
--
Posted via http://www.ruby-forum.com/.

Jeremy Woertink wrote:
> Gavin Kistner wrote:
>> It means that it found the first match starting at index 0 in the
>> string. (Try reading the documentation on the =~ method.)
>>
>
> ok, that makes sense. I did check out the docs on
> http://www.ruby-doc.org/core/
> I clicked the =~ method under Regexp and it sends me to
> rxp.match(str) => matchdata or nil
> Returns a MatchData object describing the match, or nil if there was no
> match. This is equivalent to retrieving the value of the special
> variable $~ following a normal match.
>
> which didn't say anything about indexes. Are there any other sites that
> have different documentation?
>
>
> ~Jeremy

haha, ok you can disregard that, I looked under string and seen what you
were talking about. My bad.

thanks

~Jeremy
--
Posted via http://www.ruby-forum.com/.

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If it's going to be going heavy on the regexp...... (I have no shame)

Try TextualRegexp. Seriously, it was written so you DON"T have to
hurt your brain over it.


~ Ari
English is like a pseudo-random number generator - there are a
bajillion rules to it, but nobody cares.