Array Sorting Issue

[Extension]

Hi,

I have a file in the following format:

FIELD1|FIELD2|FIELD3|FIELD4
1|90-09|LINK|A-D
2|05-09|LINK-PL|FDX

Now I'm converting the file to an array and then I'm splitting the fields. I would to sort the array by the "FIELD2".

	open(FILE,"file.dat") || die("Error !")		
	@File = map {chomp; [split /\|/, $_]} <FILE>;
	close(FILE);
	
	sort { $b->[1] cmp $a->[1] } @File;

The array is not getting sorted properly with my current data.

 

[ishnid]

Try:

@File = sort { $b->[1] cmp $a->[1] } @File;

The "sort" function doesn't sort in-place.

 

[PaulTEG]

I'd look at dumping that in a hash, and then sort the hash, and to account for possible dupes, and the (what looks like a) unique identifier.

while (<FILE>) {
  @data=split /\|/, $_;
  $hash{$data[0]."-".$data[2]}=$_;
}
close FILE;
foreach $key (sort(keys(%hash))) {
    push (@array, $hash{$key}
}

Not tested BTW


Paul
------------------------------------
Spend an hour a week on CPAN, helps cure all known programming ailments ;-)

 

[PaulTEG]

push (@array, $hash{$key});
oops

Paul
------------------------------------
Spend an hour a week on CPAN, helps cure all known programming ailments ;-)

 

[Extension]

Thank you ishnid. Learned something new ! Thanks again for your help.

Dumb question regarding arrays:
The first value of an array is always 0; I would like to know if there is an easy way to make it record #1 instead of 0 ?

Thank you

 

[Extension]

Thanks PaulTEG for your advice.

I will have to start using hashes more frequently as they are more easy to process and to manipulate with large amount of data. Thank you.

 

[MillerH]

From

http://perldoc.perl.org/perlvar.html

# $[

The index of the first element in an array, and of the first character in a substring. Default is 0, but you could theoretically set it to 1 to make Perl behave more like awk (or Fortran) when subscripting and when evaluating the index() and substr() functions. (Mnemonic: [ begins subscripts.)

As of release 5 of Perl, assignment to $[ is treated as a compiler directive, and cannot influence the behavior of any other file. (That's why you can only assign compile-time constants to it.) Its use is highly discouraged.

Note that, unlike other compile-time directives (such as strict), assignment to $[ can be seen from outer lexical scopes in the same file. However, you can use local() on it to strictly bind its value to a lexical block.

But, don't ... don't ... don't ... ever ... do that. All I can say about it.

 

[PaulTEG]

^^^ I'm with him/her

If in life, you learn to walk around obstacles, rather than right through, it exemplifies diplomacy, what we know as a good skill, to the point of appointment, and then .... it all goes horribly wrong ... or you could just take our word for it

do not, (!==doughnut) prick with $[, because of what may or may not happen ... the choice, as they say, is yours ...

--Paul

Paul
------------------------------------
Spend an hour a week on CPAN, helps cure all known programming ailments ;-)