请大家帮忙看看我这段程序运行后,怎么会丢失一行?

nv2test

有两个文件,程序目的是替换A文件中的第一个字段的同时,替换B文件中的相同字段.
文件A:
a1|kajlkj|ksjlfk|skfjls|23
a2|ljkj|skjk|24234|33
......

文件B:
b1|llkl3|c1|lkll|k9ii|234223|a1|44
b2|klkll|a1|................|c1|sf.
b3|.....|d1|................|e1|
b4|.....|a2|................|d1|
b5|.....|d2|................|a2|
....

我的方法是:

1. 
   
2. open(FHA1,"A");
   
3. open(FHA2,">A.txt");
   
4. open(FHB1,"B");
   
5. open(FHB2,">B.txt");
   
6. $data = 50000;
   
7. while($lineA = <FHA1>){
   
8.         chomp $lineA;
   
9.         ($field1,$field2,$field3,$field4,$field5) = split(/\|/,$lineA,5);
   
10.         seek(FHB1,0,0);
    
11.         while($lineB = <FHB1>){
    
12.                 chomp $lineB;
    
13.                 ( $value1,$value2,$value3,$value4,$value5,$value6,$value7,$value8 ) = split( /\|/,$lineB,8 );
    
14.                 if($value3 == $field1){
    
15.                         $value3 = $data;
    
16.                         $lineB = join('|',$value1,$value2,$value3,$value4,$value5,$value6,$value7);
    
17.                         print FHB2 $lineB,"\n";
    
18.                 }
    
19.                 elsif($value7 == $field1){
    
20.                         $value7 = $data;
    
21.                         $lineB = join('|',$value1,$value2,$value3,$value4,$value5,$value6,$value7);
    
22.                         print FHB2 $lineB,"\n";                                       
    
23.                 }
    
24.         }
    
25.         $field1 = $data++;
    
26.         $lineA = join('|',$field1,$field2,$field3,$field4,$field5);
    
27.         print FHA2 $lineA,"\n";
    
28. }
    
29. close(FHA1);
    
30. close(FHA2);
    
31. close(FHB1);
    
32. close(FHB2);
    

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可是这样做的运行的结果是,类似文件B中第三行,在写到B.txt文件中时就会丢失;
请问这种情况处理?

[ 本帖最后由 nv2test 于 2006-7-6 09:57 编辑 ]

ulmer

Hallo,

tips and tricks:
To make programming easy and clearly.
don't open many file handler and process data at same time.
Firstly load data from file and put it in a data structure (i.e. an array).
Processing different data together to make new data structure and then write them
into new files.

Sample code:

1. 
   
2. use strict;
   
3. 
   
4. open FA, 'A.txt';
   
5. my @a_lines = <FA>;
   
6. close FA;
   
7. 
   
8. open FB, 'B.txt';
   
9. my @b_lines = <FB>;
   
10. close FB;
    
11. 
    
12. my $update = 9999; # change value for all first field in file A
    
13. my @new_a = ();
    
14. my @new_b = ();
    
15. 
    
16. foreach my $a_line (@a_lines) {
    
17.     chomp $a_line;
    
18.     my @a_tmp = split /\|/, $a_line, -1;
    
19.     my $a_field_1 = $a_tmp[0];
    
20.     my $cnt_b = 0;
    
21.     foreach my $b_line (@b_lines) {
    
22.         chomp $b_line;
    
23.         my @b_tmp_new = ();
    
24.         for my $b_item (split /\|/, $b_line, -1) {
    
25.             # mapping new B
    
26.             if ($b_item eq $a_field_1) {
    
27.                 push @b_tmp_new, $update;
    
28.             } else {
    
29.                 push @b_tmp_new, $b_item;
    
30.             }
    
31.         }
    
32.         $new_b[$cnt_b] = join '|', @b_tmp_new;
    
33.         $cnt_b++;
    
34.     }
    
35.     # mapping new A
    
36.     $a_tmp[0] = $update;
    
37.     push @new_a, join '|', @a_tmp;
    
38. }
    
39. 
    
40. # debug:
    
41. print "A:\n", @a_lines;
    
42. print "B:\n", @b_lines;
    
43. print "\nNew A: \n", join "\n", @new_a;  # write it in new A file
    
44. print "\nNew B: \n", join "\n", @new_b;  # write it in new B file
    
45. print "\n";
    
46. # :~)
    
47. 
    

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Best,
    ulmer

-----
Just for Fun

nv2test

非常感谢umler!!
首先需要说明的是,我是个PERL的初学者,你回复的代码,我研究了差不多4个小时的时间,终于读懂了.从你的回复中,我学到了很多,真的!!