I am having trouble translating this into Ruby.
Here is a piece of JavaScript that does exactly what I want to do:
function get_code(str){
return str
\1
in double quotes needs to be escaped. So you want either
"Z_sdsd: sdsd".gsub(/^(Z_.*): .*/, "\\1")
or
"Z_sdsd: sdsd".gsub(/^(Z_.*): .*/, '\1')
see the docs on gsub where it says "If it is a double-quoted string, both back-references must be preceded by an additional backslash."
That being said, if you just want the result of the match you can do:
"Z_sdsd: sdsd".scan(/^Z_.*(?=:)/)
or
"Z_sdsd: sdsd"[/^Z_.*(?=:)/]
Note that the (?=:)
is a non-capturing group so that the :
doesn't show up in your match.
def get_code(str)
str.sub(/^(Z_.*): .*/, '\1')
end
get_code('Z_foo: bar!') # => "Z_foo"
Try '\1'
for the replacement (single quotes are important, otherwise you need to escape the \
):
"foo".gsub(/(o+)/, '\1\1\1')
#=> "foooooo"
But since you only seem to be interested in the capture group, note that you can index a string with a regex:
"foo"[/oo/]
#=> "oo"
"Z_123: foobar"[/^Z_.*(?=:)/]
#=> "Z_123"
"foobar".gsub(/(o+)/){|s|s+'ball'}
#=> "fooballbar"
If you need to use a regex to filter some results, and THEN use only the capture group, you can do the following:
str = "Leesburg, Virginia 20176"
state_regex = Regexp.new(/,\s*([A-Za-z]{2,})\s*\d{5,}/)
# looks for the comma, possible whitespace, captures alpha,
# looks for possible whitespace, looks for zip
> str[state_regex]
=> ", Virginia 20176"
> str[state_regex, 1] # use the capture group
=> "Virginia"
$
variables are only set to matches into the block:
"Z_sdsd: sdsd".gsub(/^(Z_.*): .*/) { "#{ $1.strip }" }
This is also the only way to call a method on the match. This will not change the match, only strip
"\1" (leaving it unchanged):
"Z_sdsd: sdsd".gsub(/^(Z_.*): .*/, "\\1".strip)