About a regular expression


T

T5in9tao Tsingtao

Hi,

I really don't unserstand why my regular expression don't scan a string.
My goal is to match in a string a domain name. I copy/past my code here:

--------------------------------

#! /usr/bin/env ruby

domain_name =
"[a-zA-Z0-9-]{1,63}\.(aero|biz|cat|com|coop|edu|gov|info|int|jobs|mil|mobi|museum|name|net|org|travel|ac|ad|ae|af|ag|ai|al|am|an|ao|aq|ar|as|at|au|aw|az|ba|bb|bd|be|bf|bg|bh|bi|bj|bm|bn|bo|br|bs|bt|bv|bw|by|bz|ca|cc|cd|cf|cg|ch|ci|ck|cl|cm|cn|co|cr|cs|cu|cv|cx|cy|cz|de|dj|dk|dm|do|dz|ec|ee|eg|eh|er|es|et|eu|fi|fj|fk|fm|fo|fr|ga|gb|gd|ge|gf|gg|gh|gi|gl|gm|gn|gp|gq|gr|gs|gt|gu|gw|gy|hk|hm|hn|hr|ht|hu|id|ie|il|im|in|io|iq|ir|is|it|je|jm|jo|jp|ke|kg|kh|ki|km|kn|kp|kr|kw|ky|kz|la|lb|lc|li|lk|lr|ls|lt|lu|lv|ly|ma|mc|md|me|mg|mh|mk|ml|mm|mn|mo|mp|mq|mr|ms|mt|mu|mv|mw|mx|my|mz|na|nc|ne|nf|ng|ni|nl|no|np|nr|nu|nz|om|pa|pe|pf|pg|ph|pk|pl|pm|pn|pr|ps|pt|pw|py|qa|re|ro|rs|ru|rw|sa|sb|sc|sd|se|sg|sh|si|sj|sk|sl|sm|sn|so|sr|st|su|sv|sy|sz|tc|td|tf|tg|th|tj|tk|tl|tm|tn|to|tp|tr|tt|tv|tw|tz|ua|ug|uk|um|us|uy|uz|va|vc|ve|vg|vi|vn|vu|wf|ws|ye|yt|yu|za|zm|zr|zw)"

string = "<p><strong><a
href=\"http://haiku-os.org\">Haïku</a></strong></p>"
result = string.scan(/#{domain_name}/)
result.each { |x| puts x }

--------------------------------

About me, there is a trouble near the dot. But normaly it's okay thanks
to ".\" ...

Thank you for help.
 
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T

T5in9tao Tsingtao

Note: in this example, I would like to save "haiku-os.org" string in
result variable.
 
Y

yermej

Hi,

I really don't unserstand why my regular expression don't scan a string.
My goal is to match in a string a domain name. I copy/past my code here:

--------------------------------

#! /usr/bin/env ruby

domain_name =
"[a-zA-Z0-9-]{1,63}\.(aero|biz|cat|com|coop|edu|gov|info|int|jobs|mil|mobi|museum|name|net|org|travel|ac|ad|ae|af|ag|ai|al|am|an|ao|aq|ar|as|at|au|aw|az|ba|bb|bd|be|bf|bg|bh|bi|bj|bm|bn|bo|br|bs|bt|bv|bw|by|bz|ca|cc|cd|cf|cg|ch|ci|ck|cl|cm|cn|co|cr|cs|cu|cv|cx|cy|cz|de|dj|dk|dm|do|dz|ec|ee|eg|eh|er|es|et|eu|fi|fj|fk|fm|fo|fr|ga|gb|gd|ge|gf|gg|gh|gi|gl|gm|gn|gp|gq|gr|gs|gt|gu|gw|gy|hk|hm|hn|hr|ht|hu|id|ie|il|im|in|io|iq|ir|is|it|je|jm|jo|jp|ke|kg|kh|ki|km|kn|kp|kr|kw|ky|kz|la|lb|lc|li|lk|lr|ls|lt|lu|lv|ly|ma|mc|md|me|mg|mh|mk|ml|mm|mn|mo|mp|mq|mr|ms|mt|mu|mv|mw|mx|my|mz|na|nc|ne|nf|ng|ni|nl|no|np|nr|nu|nz|om|pa|pe|pf|pg|ph|pk|pl|pm|pn|pr|ps|pt|pw|py|qa|re|ro|rs|ru|rw|sa|sb|sc|sd|se|sg|sh|si|sj|sk|sl|sm|sn|so|sr|st|su|sv|sy|sz|tc|td|tf|tg|th|tj|tk|tl|tm|tn|to|tp|tr|tt|tv|tw|tz|ua|ug|uk|um|us|uy|uz|va|vc|ve|vg|vi|vn|vu|wf|ws|ye|yt|yu|za|zm|zr|zw)"

string = "<p><strong><a
href=\"http://haiku-os.org\">Haïku</a></strong></p>"
result = string.scan(/#{domain_name}/)
result.each { |x| puts x }

--------------------------------

About me, there is a trouble near the dot. But normaly it's okay thanks
to ".\" ...

Thank you for help.

Since your first "\." is inside a double-quoted string, it being put
in the regex as just ".". Either define domain_name with "\\." in
place of "\." or use single quotes instead of double.

Or you could define domain_name to be the regex:

domain_name = /[a-zA-Z0-9-]{1,63}\.(aero|biz|cat|[long regex cut]/
...
result = string.scan(domain_name)
 
T

T5in9tao Tsingtao

Thank you. But I belive that don't work yet, even if I update the code
like this:

--------------------------------

domain_name = /[a-zA-Z0-9-]{1,63}\.(aero|biz|com|org)/

string = '<p><strong><a
href="http://haiku-os.org">Haïku</a></strong></p>'
result = string.scan(domain_name)
result.each { |x| puts x }
 
P

Phrogz

Thank you. But I belive that don't work yet, even if I update the code
like this:

--------------------------------

domain_name = /[a-zA-Z0-9-]{1,63}\.(aero|biz|com|org)/

string = '<p><strong><a
href="http://haiku-os.org">Haïku</a></strong></p>'
result = string.scan(domain_name)
result.each { |x| puts x }

domain_name = /[a-zA-Z0-9-]{1,63}\.(?:aero|biz|com|org)/

If a regular expression has capture groups in it, String#scan returns
those groups, not the entire matched expression. Placing the ?: inside
the parentheses instructs Ruby not to treat the contents as a capture
group.
 
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T

T5in9tao Tsingtao

Gavin said:
result.each { |x| puts x }
domain_name = /[a-zA-Z0-9-]{1,63}\.(?:aero|biz|com|org)/

If a regular expression has capture groups in it, String#scan returns
those groups, not the entire matched expression. Placing the ?: inside
the parentheses instructs Ruby not to treat the contents as a capture
group.

Thank you Gavin Kistner! That's working perfectly.
 
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