using variables in regular expressions

[Damphyr]

Being lazy, forgetful and generally very bad with regular expressions
leads me to post this question:

How can I use the contents of a variable as a pattern in a regular
expression?

I get a list of files from a set of paths and I want to do the following

repo=list_files paths
repo.collect!{|entry|
entry.gsub(/{variable_with_the root_I_want_to_substitute}/,"")
}

pretty straightforward no?
V.-



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[Robert Klemme]

Being lazy, forgetful and generally very bad with regular expressions
leads me to post this question:

How can I use the contents of a variable as a pattern in a regular
expression?

I get a list of files from a set of paths and I want to do the following

repo=list_files paths
repo.collect!{|entry|
entry.gsub(/{variable_with_the root_I_want_to_substitute}/,"")
}

using gsub! is more efficient and better use %r{} because Regexp.quote
does not quote "/":

repo=list_files paths
repo.each {|entry|
entry.gsub!(%r{#{Regexp.quote(variable_with_the
root_I_want_to_substitute)}},"")
}

Regards

robert

 

[Sabby and Tabby]

using gsub! is more efficient and better use %r{} because Regexp.quote
does not quote "/":

repo.each {|entry|
entry.gsub!(%r{#{Regexp.quote(variable_with_the
root_I_want_to_substitute)}},"")
}

Don't need %r{}. A slash "/" in interpolated variables is harmless.
Add anchor, unless removing root from middle of path is desirable.
Add /o modifier:

entry.gsub!(/^#{Regexp.quote(root)}/o, "")

 

[Robert Klemme]

Don't need %r{}. A slash "/" in interpolated variables is harmless.
True.

Add anchor, unless removing root from middle of path is desirable.

I had that in my first version, but apparently the "^" didn't make it into
the posting. Thx!

Add /o modifier:

I wouldn't do that if the rx was in a method that received the path as
parameter. Could lead to surprising effects.

entry.gsub!(/^#{Regexp.quote(root)}/o, "")

Cheers

robert