Re: Extracting selected fields form file record (updated)

ehm ...

> > spaces before and after

the spaces before are IMHO best dealt by stripping them before splitting. °

$line =~ s/^\s+//;

Even your pseudo python code can't do this in a one-liner with split (IMHO).

But more importantly your definition of "field" is fuzzy now.

Please clarify

how do you allow empty fields?
are all whitespace characters as separator allowed (like tab...)?
are multiple whitespace characters as separator allowed?

update

provided there are no "empty fields" and "multiple whitespaces" are allowed as separators:

You can use a regex like /(\S+)/g ( \S is non-whitespace, the opposite of \s)

Debugger demo:

  DB<35> $line = " a0 a1 a2 a3 a4 a5 a6 a7 a8 a9 \n"

  DB<36> x ($line =~  /(\S+)/g)[0,1,3,5,7,9]
0  'a0'
1  'a1'
2  'a3'
3  'a5'
4  'a7'
5  'a9'

  DB<37>
[download]

Cheers Rolf
_{(addicted to the Perl Programming Language :)

Wikisyntax for the Monastery}

update

°) or by using the magic of ' ' soonix showed us here.

Comment on Re: Extracting selected fields form file record (updated) Select or Download Code

Replies are listed 'Best First'.
Re^2: Extracting selected fields form file record (updated) by rsFalse (Chaplain) on Feb 07, 2022 at 12:27 UTC
We can omit parentheses, i.e. capture group number 1 isn't necessary. `my( $first, $second, $third, $fourth, $fifth, $sixth ) = ( $line =~ m/ +\S+/g )[ 0, grep { $_ % 2 == 1 } 1 .. 9 ];` [download]	[reply] [d/l]
Re^2: Extracting selected fields form file record (updated) by Anonymous Monk on Feb 07, 2022 at 12:32 UTC
Thanks everyone. Using ' ' is working as I need on records from an ASCII file. And I'm going to load the records with `File::Slurp`, so I don't care of chomp: `use File::Slurp qw(read_file); my @lines = read_file('/path/file',chomp=>1);` [download]	[reply] [d/l] [select]
Re^3: Extracting selected fields form file record (don't use File::Slurp) by eyepopslikeamosquito (Archbishop) on Feb 08, 2022 at 11:40 UTC
Noone even mentioned File::Slurp! :) If you must use a module for this, may I suggest Path::Tiny or File::Slurper? See File::Slurp is broken and wrong by Leon Timmermans for why. Update: Agree with haukex below to just do it idiomatically without a module: `my $string = do { local $/; <$fh> }` See also: Any downsides to this slurp idiom? by haukex (2018 - prior discussion of this problem)	[reply] [d/l]
Re^4: Extracting selected fields form file record by haukex (Archbishop) on Feb 08, 2022 at 12:25 UTC
If you must use a module for this, may I suggest Path::Tiny or File::Slurper? While those modules are nice, I personally find it a bit difficult to keep track of all of the different modules' opinions on how to best slurp files. And considering that slurping a file takes at most two lines of pure Perl code and I remain in full control over layers etc., I no longer see the need to load a module just for that. The following only requires knowing some of the details of layers, such as knowing the effect of `${^OPEN}`, using `:encoding(UTF-8)` instead of `:utf8`, and that UTF-16 files on Windows require the layers `:raw:encoding(UTF-16):crlf` (the latter two being documented in PerlIO and "open" Best Practices). `my $all = do { open my $fh, '<', $filename or die "$filename: $!"; local $/; <$fh> }; my @lines = do { open my $fh, '<', $filename or die "$filename: $!"; <$fh> }; chomp @lines;` [download]	[reply] [d/l] [select]
Re^5: Extracting selected fields form file record by choroba (Cardinal) on Feb 08, 2022 at 13:07 UTC


Do you know where your variables are?
	PerlMonks