IF NOT! IF NOT!

[Anonymous Monk]

Hello,

I'm writing this script and I'm stuck.

I need an if statement to say something like "if grep can't find 'home' in a word, print the word."

I started out with:

if (!grep /home/, $words[$x]) {
    print $words[$x];
}

This takes place in a loop where at the end $x is increased by one.
If some one could help me I would be so grateful.

Thanks

Edit: chipmunk 2001-08-02

[abstracts]

Hello,

I think this is what you wanted to do:

my @list = qw/hello hunn I am home homealone myhome myhomealone/;

print "$_\n" for grep {$_ !~ /home/} @list;

# hello
# hunn
# I
# am

Hope this helps,,,

Aziz,,,

[damian1301]

A bit excessive, this will work just fine.



grep{$_!~/home/&&print"$_\n"} @list;

Which results the same as yours.

UPDATE: Changed map to grep so there would be no void context stuff, thanks runrig.



$_.=($=+(6<<1));print(chr(my$a=$_));$^H=$_+$_;$_=$^H;
print chr($_-39); # Easy but its ok.

[abstracts]

Hello

You can go even with

/home/||print"$_\n"for@list

But this is not golf :-)

Aziz,,,

[runrig]

And that is using map in a void context (creating an array with map and throwing it away). Better to just use a for loop:

/home/ and print "$_\n" for @list;

Update: Damian's right (in reply below). reverse the logic:

/home/ or print "$_\n" for @list;

[twerq]

using perl regular expressions, try:

   foreach my $word (@words) {
      print "$word\n"
         if ($word =~ /home/);
   }



--twerq

[myocom]

...except that you got the logic backwards.

I need an if statement to say something like "if grep can't find 'home' in a word, print the word."

foreach (@words) {
    print "$_\n" unless /home/;
}

[suaveant]

Grep returns a list, so I'm not sure what the ! will do... you probably either want

unless(grep /home/, @words) {
  print $words[$x];
}

Your problem is you need to pass grep an array @words, not part of the array $words[$x]... if $words[$x] contains a sub array you need to dereference it like... @{$words[$x]}

It would help if you said a little more about what the data is

Update Nevermind... from other people responses I see what is going on... yeah, you probably want

print $words[$x] if $words[$x] =~ /home/;

oops :)

                - Ant

[dragonchild]

As an aside, the construct ! grep EXPR, LIST is used in a boolean context. Either grep returns a list or it doesn't. ! evaluates in a boolean context. A list is TRUE and no list is FALSE.

I've used it a lot in extended EXPR's, so that I don't have to work through the negation of my && or || that sending if to unless (or vice-versa) would do.

--------
/me wants to be the brightest bulb in the chandelier!

[Hofmator]

As an aside, the construct ! grep EXPR, LIST is used in a boolean context. Either grep returns a list or it doesn't. ! evaluates in a boolean context. A list is TRUE and no list is FALSE.

Not the best way to put it, IMHO ... to clarify: in scalar context grep returns the number of times it matched. So if it didn't match anything, it returns 0 which evaluates to false. Otherwise it returns a positive number which evaluates to true.

The boolean context is enforced by the if (and by the !), so that the grep in if (grep /blah/, @array)also evaluates in boolean context.

-- Hofmator

[suaveant]

Ahhh... I wasn't sure... the code had me a bit confused anyway... backwards logic does that :)

                - Ant