Regex: changing longer patterns to shorter ones

[Steventangle]

ITEM 0

How does one go about changing a longer pattern to a shorter one? For
instance, I try

$string =~ tr/longer/short/;

but it doesn't change "This is a longer pattern." to "This is a short
pattern." Rather, it does a one-for-one replacement yielding "This is a
shortr pattrro."

ITEM 1

How do you use variables in regexes? For instance, if I wanted to replace
the variable $var with $string, what's the tr or s syntax for it?

Thanks for the help,
Steve

 

[Gunnar Hjalmarsson]

How does one go about changing a longer pattern to a shorter one? For
instance, I try

$string =~ tr/longer/short/;

but it doesn't change "This is a longer pattern." to "This is a short
pattern."

Not surprising, since you are using the tr/// operator, which doesn't
include any pattern or regular expression.

Rather, it does a one-for-one replacement yielding "This is a
shortr pattrro."

Yep, that's what the tr/// operator does.

Try the s/// operator instead.

perldoc perlop

How do you use variables in regexes? For instance, if I wanted to replace
the variable $var with $string, what's the tr or s syntax for it?

s/$var/$string/

perldoc perlop

 

[Tad McClellan]

How do you use variables in regexes?

The same way that you use them in double quoted strings.

For instance, if I wanted to replace
the variable $var with $string, what's the tr or s syntax for it?

Show us what you have tried and we will help you fix it.

 

[Chris Mattern]

ITEM 0

How does one go about changing a longer pattern to a shorter one? For
instance, I try

$string =~ tr/longer/short/;

but it doesn't change "This is a longer pattern." to "This is a short
pattern." Rather, it does a one-for-one replacement yielding "This is a
shortr pattrro."

That's correct. That's what tr/// does. What you want is s///

ITEM 1

How do you use variables in regexes? For instance, if I wanted to replace
the variable $var with $string, what's the tr or s syntax for it?

You type $var right into the regex. It does interpolate, you know.

Thanks for the help,
Steve

--
Christopher Mattern

"Which one you figure tracked us?"
"The ugly one, sir."
"...Could you be more specific?"

 

[StevenTangle]

Yes, Gunnar, you were right on the money. Converting a longer string to a
shorter string became very easy after I used s/longer/short as
tr/longer/short does a one-to-one replacement of the letters. Also,
s/$var/$string works fines.

Thanks!
Steve