perl如何判断文件结束

wanghuanan

Learning.Perl
看"输入与输出"

charmkid

原帖由 wanghuanan 于 2009-12-16 21:04 发表
Learning.Perl
看"输入与输出"

我想处理一个文本文件的偶数行，但是下面的程序一直跑不通，哪位大侠能帮我看看。
#!/usr/bin/perl -w
open (INFILE, "diff.txt");
open (OUTFILE, ">Result.txt");

print "Please Input delta T (us):";
$r=<STDIN>;
chomp $r;
$r=$r*0.000001;

$x=0;
$y=1;

while (<INFILE>)

{

while ($x==0)
  {$line=<INFILE>;
   $linebk1=$line;
   $line=~ s/"time" //;
   $time1=$line;
   $line=<INFILE>;
   $x=$line;
   }      

while ($x==1)
  {$line=<INFILE>;
   $linebk2=$line;
   $line=~ s/"time" //;
   $time2=$line;
   $line=<INFILE>;
   $x=$line;
   }      
   

$t=$time2-$time1;

if ($t>$r)
   {print "$y FAILED\n";
    print OUTFILE "$y FAILED\n";
    print OUTFILE "ERROR START: $linebk1";
    print OUTFILE "ERROR ENDED: $linebk2";
    print OUTFILE "\n";
   }
else {print "$y SUCCESS\n";
      print OUTFILE "$y SUCCESS\n";
      print OUTFILE "SUCCESS START: $linebk1";
      print OUTFILE "SUCCESS ENDED: $linebk2";
      print OUTFILE "\n";
     }

$y++

}

close (INFILE);
close (OUTFILE);

charmkid

还是搞不定……

Perl_Er

你用$.啊,  $. % 2 == 0

scrit

看小骆驼 defined 就知道了

shangat

1. use strict;
   
2. use warnings;
   
3. 
   
4. 
   
5. open INFILE,"diff.txt" or die "$!\n";
   
6. open OUTFILE,">Result.txt" or die "$!\n";
   
7. 
   
8. print "Please input delta T (us):";
   
9. chomp ( my $r = <> );
   
10. $r *=0.000001;
    
11. 
    
12. my $x = 0;
    
13. my $y = 1;
    
14. my $check = 1;
    
15. 
    
16. while <FILE> ) {
    
17.         unless ( $check % 2 ) {
    
18.                 # 你的操作#
    
19.         }
    
20.         $check++;
    
21. }
    
22. close FILE;
    
23. close OUTFILE;
    

复制代码

看书，静下心来看.......

szedwin

根据楼上的方法写了一个脚本:

#!/bin/env perl

use strict;


open (FH, "<", "/root/userlist.txt") or die "cannot open the file $!\n";

my $check = 1;

while (<FH>){
        chomp;
        if ($check % 2 == 0){
                print "$_\n";
        }
        $check++;
}

仅供参考~~

iamblackwolf

while <INFILE>,,每执行一次<INFILE>指针就向后移动一行了，所以也许取不到你想要的值吧..