Asp Forum - gsub wrapper - comp.lang.ruby

Quiroz, Hector

3/2/2006 11:10:00 PM

Help!

How do I get $1, $2, and $3 to get interpolated in the following
snippet?

string = 'This is a test of the emergency'
regexp = Regexp.new('(\W)+(\w\w)(\W)+')
replacement = '$1->$2<-$3'
user_wants_upcase=FALSE

# Note: All variables above are set by the user of the program, so I
don't know
# what they will contain before runtime.

string.gsub!(regexp) {
return_value = string # Here, how do I get $1, $2, and $3 to
interpolate?

if (user_wants_uppercase)
return_value.upcase! || return_value
end

return_value
}

I want return_value to be -> 'This ->is<- a test ->of<- the emergency'

Note: I know that I can get it to work with the non-block version of
gsub! but I need to use the block version.

Thanks

Hector

--
Posted via http://www.ruby-....

5 Answers

Yuu

3/2/2006 11:25:00 PM

Hector wrote:
> Help!
>
> How do I get $1, $2, and $3 to get interpolated in the following
> snippet?
>
> string = 'This is a test of the emergency'
> regexp = Regexp.new('(\W)+(\w\w)(\W)+')
> replacement = '$1->$2<-$3'

If you have '"#{$1}->#{$2}<-#{$3}"', you can eval
it in the block. This is probably a bad idea, though.

To make this a bit safer, you would probably want the
user to give you some kind of a sprintf-style string
that you format inside the block. This might limit
the user to strictly linear numbering or something.

> user_wants_upcase=FALSE
>
> # Note: All variables above are set by the user of the program, so I
> don't know
> # what they will contain before runtime.
>
> string.gsub!(regexp) {
> return_value = string # Here, how do I get $1, $2, and $3 to
> interpolate?
>
> if (user_wants_uppercase)
> return_value.upcase! || return_value
> end
>
> return_value
> }
>
> I want return_value to be -> 'This ->is<- a test ->of<- the emergency'
>
> Note: I know that I can get it to work with the non-block version of
> gsub! but I need to use the block version.
>
> Thanks
>
> Hector

E

--
Posted via http://www.ruby-....

Logan Capaldo

3/2/2006 11:29:00 PM

On Mar 2, 2006, at 6:09 PM, Hector wrote:

> Help!
>
> How do I get $1, $2, and $3 to get interpolated in the following
> snippet?
>
> string = 'This is a test of the emergency'
> regexp = Regexp.new('(\W)+(\w\w)(\W)+')
> replacement = '$1->$2<-$3'
> user_wants_upcase=FALSE
>
> # Note: All variables above are set by the user of the program, so I
> don't know
> # what they will contain before runtime.
>
> string.gsub!(regexp) {
> return_value = string # Here, how do I get $1, $2, and $3 to
> interpolate?
>
> if (user_wants_uppercase)
> return_value.upcase! || return_value
> end
>
> return_value
> }
>
> I want return_value to be -> 'This ->is<- a test ->of<- the emergency'
>
> Note: I know that I can get it to work with the non-block version of
> gsub! but I need to use the block version.
>
> Thanks
>
> Hector
>
> --
> Posted via http://www.ruby-....
>

assuming I understand your question:

str = "#{$1}->#{$2}<-#{$3}"

Alternatively:

str = "#$1->#$2<-#$3"

Timothy Goddard

3/3/2006 1:34:00 AM

$1 is a global variable which is set to the value matched by the
bracketed bits. You just treat it like any string.

e.g. "The first parameter was #$1" or number = $2.to_f

In gsub substitutions the letters '\N' in the substitution text, where
N is a number from 1 to 9, will be replaced by the substituted
sequence. If you use double quotes, you will need two backslashes
because this is not a normal escape sequence.

str = "We love Ruby"
puts str.gsub(/We (\w+) \w+/, 'Why do we \1 it?')
puts str.gsub(/(\w+)$/, "it because \\1 allows us to do cool stuff!")

Robert Klemme

3/3/2006 8:35:00 AM

Hector wrote:
> Help!
>
> How do I get $1, $2, and $3 to get interpolated in the following
> snippet?
>
> string = 'This is a test of the emergency'
> regexp = Regexp.new('(\W)+(\w\w)(\W)+')
> replacement = '$1->$2<-$3'
> user_wants_upcase=FALSE
>
> # Note: All variables above are set by the user of the program, so I
> don't know
> # what they will contain before runtime.
>
> string.gsub!(regexp) {
> return_value = string # Here, how do I get $1, $2, and $3 to
> interpolate?
>
> if (user_wants_uppercase)
> return_value.upcase! || return_value
> end
>
> return_value
> }
>
> I want return_value to be -> 'This ->is<- a test ->of<- the emergency'
>
> Note: I know that I can get it to work with the non-block version of
> gsub! but I need to use the block version.

In your case you don't even need groups, because you can nicely anchor the
expression on word boundaries:

>> upcase=true
=> true
>> 'This is a test of the emergency'.gsub(/\b\w\w\b/) {|m| "->" << (upcase
? m.upcase : m) << "<-"}
=> "This ->IS<- a test ->OF<- the emergency"

Otherwise

>> 'This is a test of the emergency'.gsub(/(\W)+(\w\w)(\W)+/) {|m|
"#$1->#{upcase ? $2.upcase : $2}<-#$3"}
=> "This ->IS<- a test ->OF<- the emergency"

Note: #$1 in a double quoted string is a shortcut for #{$1}.

Kind regards

robert

atpgroups

5/8/2008 8:56:00 AM

On 8 May, 01:13, straightedge32
<straightedg...@discussions.microsoft.com> wrote:

> I tried doing just what you said, copying the syntax appropriately, but I
> just get an error message stating "Run time error 438: Object Doesn't Support
> this property or method".

Sorry, my mistake, I typed that reply last night on a machine without
Excel installed and I got it wrong (twice)

Set myRange = wrksht.Range(wrksht.Cells(nCurrRow, 8),
wrksht.Cells(nCurrRow, 16))
wrksht.Cells(nCurrRow, 17).Value =
Application.WorksheetFunction.Average(myRange.Value)

Will work. "Object Doesn't Support this property or Method" was due to
me inventing a new method "WorkSheetFunctions" when it is
"WorkSheetFunction"
Also, the .Value applies to myRange, not to Average() so it was in the
wrong place.
Sorry for any confusion I might have caused.

comp.lang.ruby

gsub wrapper

Quiroz, Hector

Yuu

Logan Capaldo

Timothy Goddard

Robert Klemme

atpgroups

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