Question

#!/usr/bin/perl                                                                                                                                                                  

use strict;
use warnings;

my $directory = shift @ARGV or die "Please specify a directory";

if(opendir(DIR , $directory))

{
    my @files = readdir(DIR);

    @files = grep(/\.out/ , @files);

    closedir(DIR);

    foreach my $file (@files)
    {
        if ( -z $directory.$file )
        {
            next;
        }
        ProcessData($directory.$file);
    }

}
else
{
    print STDERR "unable to open current directory\n";
}

sub ProcessData
{
    my ($file) = @_;

    if(open(FILE , $file))
    {
        my @lines = <FILE>;
        my $lines =~ s/\,//g;
        my @fields = split(/\s+/,$lines[1]);

        print "$fields[1] $fields[2] $fields[3] $fields[4] $fields[5]\n";

        close FILE;
    }

    else
    {
        print STDERR "Can't open $file\n";
    }

我正在尝试将一组文件的第二行拆分为空格，删除所有逗号，然后打印一些字段。打印了正确的字段，但逗号仍然存在，我收到错误消息：Use of uninitialized value $lines in substitution (s///)。我是Perl的新手，对此非常困惑。任何帮助将非常感激。提前谢谢。

Answer 1

好的，你离我不太远。问题是你写了my $lines =~ s/\,//g;而不是$lines[1] =~ s/\,//g;。

#!/bin/perl
use strict;
use warnings;

my $file = "input.txt";
open my $fh, "<", $file or die "$!";

my @lines = <$fh>;
$lines[1] =~ s/\,//g; # This is the line that needed to be fixed
my @fields = split('\s+', $lines[1]);
print "$fields[1] $fields[2] $fields[3] $fields[4] $fields[5]\n";
close $fh;

输出：

$ cat input.txt
  UniProtAC，Nat，Resnum，Mut，Prediction，Confidence
  AvrgALL：P06132，ARG，332，HIS，PD，0.62
  $ perl sub.pl
  P06132 ARG 332 HIS PD

我想指出的另一件事是：What's the best way to open and read a file in Perl?。使用open的3参数形式通常更好，使用词法文件句柄也是如此。

perl中的替换错误

1 个答案: