$ perl -Mstrict -Mwarnings -e '(a,b,c,d,e,f) = [line.split()[i] for i in (0,1,3,5,7,9)]'
Bareword "line" not allowed while "strict subs" in use at -e line 1.
syntax error at -e line 1, near ")["
Execution of -e aborted due to compilation errors.

##</code><code>##

$ perl -E '$_ = " a0 a1 a2 \n"; my ($x, @y) = split; say "|$x|@y|";'
|a0|a1 a2|

$ perl -E '$_ = " a0 a1 a2 \n"; my ($x, @y) = split " "; say "|$x|@y|";'
|a0|a1 a2|

$ perl -E '$_ = " a0 a1 a2 \n"; my ($x, @y) = split / /; say "|$x|@y|";'
||a0 a1 a2
|

$ perl -E '$_ = " a0 a1 a2 \n"; my ($x, @y) = split /\s+/; say "|$x|@y|";'
||a0 a1 a2|

##</code><code>##

my @wanted = (extraction_function($string))[0, 1, 3];
my ($f1, $f2, undef, $f3) = extraction_function($string);