"(a,b,c,d,e,f) = [line.split()[i] for i in (0,1,3,5,7,9)]"
$ 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.
So, step one would be to learn Perl. See "Perl introduction for beginners".
"... extract with a one-line instruction ..."
Ask yourself why you think this requirement is necessary.
It rarely has any benefits.
It will often reduce readability and, as such, make your code more error-prone.
"... extract ... from a file record ..."
For records with fixed-width records, use unpack".
See the perlpacktut tutorial;
the "Packing Text" section has an example showing exactly how to do this.
For records with variable-width records, use split.
Do be aware of these differences (the linked documentation has details):
$ 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 "|$x|@y
+|";'
||a0 a1 a2|
"... extract ... some selected fields ..."
There are a variety of ways to achieve this.
The best one to choose will probably depend on how you want to subsequently process the selected fields.
Here are a couple of examples:
my @wanted = (extraction_function($string))[0, 1, 3];
my ($f1, $f2, undef, $f3) = extraction_function($string);
|