Re: Perl Idioms Explained

in reply to Perl Idioms Explained - !!expr

Can you comment on the alternatives?

return grep { $_ eq $_[0] } @_[ 1 .. $#_ ];

# or

return ~~grep { $_ eq $_[0] } @_[ 1 .. $#_ ];

# or

my $searched = shift;
return !!grep { $_ eq $earched } @_;
[download]

Should I use them? And if not, why?

Thanks

Comment on Re: Perl Idioms Explained - !!expr Download Code

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Re^2: Perl Idioms Explained - !!expr by broquaint (Abbot) on Jul 14, 2004 at 13:17 UTC
`return grep { $_ eq $_[0] } @_[ 1 .. $#_ ];` [download] Depending on context this will return different things, whereas `!!expr` will always return a boolean value. `return ~~grep { $_ eq $_[0] } @_[ 1 .. $#_ ];` [download] This will return the number of elements returned by `grep` as opposed to `!!expr` which, again, will return a boolean value. Of course both of the above are valid in appropriate situations, but if you just want a boolean value then `!!expr` is an appropriate idiomatic solution. HTH `_________ broquaint`	[reply] [d/l] [select]
Re^2: Perl Idioms Explained - !!expr by japhy (Canon) on Jul 14, 2004 at 14:46 UTC
I like `~~EXPR` as a brief (read: obfuscated) way to enforce scalar context on an expression; it only renders the return value unusable if `EXPR` is a reference. _____________________________________________________ Jeff `japhy` Pinyan, P.L., P.M., P.O.D, X.S.: Perl, regex, and `perl` hacker How can we ever be the sold short or the cheated, we who for every service have long ago been overpaid? ~~ Meister Eckhart	[reply] [d/l]
Re^2: Perl Idioms Explained - !!expr by davidrw (Prior) on Nov 05, 2005 at 02:55 UTC
I would also mention just a simple ternary operator as an alternative: `return grep($_ eq $_[0], @_[ 1 .. $#_ ]) ? 1 : '';` [download] or, more generally the equivalent to `!!$expr` is (some of the parens are optional depending on context): `(($expr)?1:'')` [download]	[reply] [d/l] [select]

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