Re: substition in perl

dennisha...@xxxxxxxxx wrote:

Trying to figure out the substitution operator in Perl.

The documentation shows the syntax as

s/PATTERN/REPLALCEMENT/

and explains that the operator searches a string for PATTERN and
replaces that match with the REPLACEMENT text.

My question then is this. What string is being searched? The
documention goes on to say that if no string is specified, the $_
variable is search.

PATTERN is searched and replaced by REPLACEMENT.

Example:
$s = 'ABC'; # assign value ABC to variable $s
$s =~ s/B/D/; # replace B into D in variable $s
print $s; # print the result (ADC)

What is the $_ variable?

This is the default variable. "where no parameter name is given for"

Example:
for (1..5) {
print $_;
}
# this prints 1 2 3 4 5 (each time the loop is being passed)

It would be the same as
for $number (1..5) {
print $number;
}

See http://learn.perl.org/

--
Bart

.

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