G'day Clovis_Sangrail,

That's a mistake that I also seem to make from time to time. [I see ++runrig has provided an explanation.]

I usually use map with braces so when I get a list of boolean values returned from something like:

map { s/match/replace/ } @array
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It's easily fixed like this:

map { s/match/replace/; $_ } @array
[download]

As you've been delving into the map documentation to understand more closely how map operates, you might also be interested to know that you can return nothing from a map expression by causing the expression to be evaluated as an empty list. For example, this code:

my @x = qw{a b a c bab aca};
my @y = map { /(.?a.?)/ ? $1 : () } @x;
print "|$_|\n" for @y;
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outputs:

|a|
|a|
|bab|
|ac|
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Also note how that differs from grep which you could emulate with that map expression by changing $1 to $_. This code:

my @x = qw{a b a c bab aca};
my @y = map { /(.?a.?)/ ? $_ : () } @x;
print "|$_|\n" for @y;
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and this code

my @x = qw{a b a c bab aca};
my @y = grep { /(.?a.?)/ } @x;
print "|$_|\n" for @y;
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both produce identical output:

|a|
|a|
|bab|
|aca|
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Obviously, there's really no point in writing that extra code (and, presumably, causing the extra processing) to make map emulate grep. However, it's feasible that you could have a function that operated as either based on a flag — I can't think of a situation where I've ever needed to do that but, if it did arise, it could be easily implemented like this:

$ perl -e '
    my $use_grep = 0;
    my @x = qw{a b a c bab aca};
    my @y = map { /(.?a.?)/ ? $use_grep ? $_ : $1 : () } @x;
    print "|$_|\n" for @y;
'
|a|
|a|
|bab|
|ac|
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$ perl -e '
    my $use_grep = 1;
    my @x = qw{a b a c bab aca};
    my @y = map { /(.?a.?)/ ? $use_grep ? $_ : $1 : () } @x;
    print "|$_|\n" for @y;
'
|a|
|a|
|bab|
|aca|
[download]