Re: how do I use s///e

In a templating system a substitution of this form can be used to do a lookup on variables being substituted with replacement from a pre-populated hash.

my %myHash = (hello=>"Howdy", goodbye=>"See ya");

while (<DATA>)
{
    s/\$(\w+)/$myHash{$1}/eg;
    print;
}
__DATA__
When I want to say hello I say $hello.
When I want to say goodbye I say $goodbye!
[download]

Update Whoops! Thanks Abigail! This started as an example that used a sub to do the look up in a database but I got all lazy and just did it as a hash. Some revised (incomplete) code below.

s/\$(\w+)/dbLookup($1)/eg;

sub dbLookup {
# Do database lookup (which would take a few more lines!)
return $lookedup ? $lookedup : '';
}
[download]

Comment on Re: how do I use s///e Select or Download Code

Replies are listed 'Best First'.
Re: how do I use s///e by Abigail-II (Bishop) on Jan 26, 2004 at 17:43 UTC
There's no point in using `/e` in your code. Removing the `/e` yields the same results. Abigail	[reply]
Re: Re: how do I use s///e by ysth (Canon) on Jan 26, 2004 at 23:16 UTC
To expand on this, whenever you have a (update: just) variable in the substitution, it's as if you said /e. In a sense, then, /e just becomes syntactic sugar that you can do away with: `$ echo with bright knives he releaseth my soul \| perl -wpe's/(\w+)/${\ +ucfirst($1)}/g' With Bright Knives He Releaseth My Soul` [download]	[reply] [d/l]