parsing a perl string 2

jcarrott · Jun 3, 2009

I am trying to read an input line and if the first field is H and the second field is 0000, then read the tenth field (which is 1533864 with 4 leading spaces). I need to check the first digit; if it is a 1 then change field[1] from 0000 to 0120, if it is 7 then change field[1] from 0000 to 0710, and if it is 8 then change field[1] from 0000 to 0800.

The program drops me into the inner loop for 1 and then again for 8 and the value of field[1] is never changed.

Can somebody please point out what I did wrong.

My input data is:
H,0000, 514659,GHXPCCONNECT810,45066599,,,,,,1533864,,,,,,,,20090529,,,,622.60
D,0000, 514659,GHXPCCONNECT810,45066599,,1,,,,1533864,,,,,,,,,,,,,,,,,,,,,,,,,

This 2 lines of data.

The program is:

foreach $line (<MyInFile>)
{
@field = split(/\,/, $line);
@numb = $field[10];
print $numb[0];

if ($field[0] == "H")
{
if ($field[1] == "0000")
{
if ($numb[0] =~ m/1/) # PO number starts with a 1
{
$field[1] = "0120";
print MyInFile $line;
}
if ($numb[0] =~ m/7/) # PO number starts with a 7
{
$field[1] = "0710";
print MyInFile $line;
}
if ($numb[0] =~ m/8/) # PO number starts with a 8
{
$field[1] = "0800";
print MyInFile $line;
}
}
}
}

brigmar · Jun 3, 2009

First, you're trying to print to your INPUT file.
You need to create an OUTPUT file where you do your printing.

Second, you're updating $field[1], but not regenerating $line (via 'join').

jcarrott · Jun 3, 2009

Brigmar, thanks I do not normally work in Perl. Can I open the file as input and output? Or do I need a new output, then rename or copy it to the name of the input file?

I will do some checking into the "join".

mikrom · Jun 3, 2009

Hi jcarrot,

Here is your example:

Given is this file
jcarrot_in.txt

Code:

H,0000,   514659,GHXPCCONNECT810,45066599,,,,,,1533864,,,,,,,,20090529,,,,622.60
D,0000,   514659,GHXPCCONNECT810,45066599,,1,,,,1533864,,,,,,,,,,,,,,,,,,,,,,,,, 
H,0000,   514659,GHXPCCONNECT810,45066599,,,,,,78910,,,,,,,,20090529,,,,622.60
H,0000,   514659,GHXPCCONNECT810,45066599,,,,,,89123,,,,,,,,20090529,,,,622.60

This is your corrected Perl-script
jcarrot.pl

Code:

[COLOR=#804040][b]use strict[/b][/color];

[COLOR=#804040][b]open[/b][/color]([COLOR=#008080]MyInFile[/color], [COLOR=#ff00ff]"[/color][COLOR=#ff00ff]jcarrot_in.txt[/color][COLOR=#ff00ff]"[/color]) 
[COLOR=#804040][b]or[/b][/color] [COLOR=#804040][b]die[/b][/color] [COLOR=#ff00ff]'[/color][COLOR=#ff00ff]Could not open file for reading[/color][COLOR=#ff00ff]'[/color];

[COLOR=#804040][b]open[/b][/color]([COLOR=#008080]MyOutFile[/color], [COLOR=#ff00ff]"[/color][COLOR=#ff00ff]>jcarrot_out.txt[/color][COLOR=#ff00ff]"[/color]) 
[COLOR=#804040][b]or[/b][/color] [COLOR=#804040][b]die[/b][/color] [COLOR=#ff00ff]'[/color][COLOR=#ff00ff]Could not open file for writing[/color][COLOR=#ff00ff]'[/color];

[COLOR=#804040][b]while[/b][/color] ([COLOR=#804040][b]my[/b][/color] [COLOR=#008080]$line[/color]=[COLOR=#008080]<MyInFile>[/color]){
  [COLOR=#804040][b]chomp[/b][/color]([COLOR=#008080]$line[/color]);
  [COLOR=#0000ff]#print "\$line='$line'\n";[/color]
  [COLOR=#804040][b]my[/b][/color] [COLOR=#008080]@field[/color] = [COLOR=#804040][b]split[/b][/color]([COLOR=#804040][b]/[/b][/color][COLOR=#ff00ff],[/color][COLOR=#804040][b]/[/b][/color], [COLOR=#008080]$line[/color]);
  [COLOR=#0000ff]#print "\@field = @field\n";[/color]
  [COLOR=#804040][b]my[/b][/color] [COLOR=#008080]$numb[/color] = [COLOR=#804040][b]substr[/b][/color]([COLOR=#008080]$field[/color][[COLOR=#ff00ff]10[/color]],[COLOR=#ff00ff]0[/color],[COLOR=#ff00ff]1[/color]); [COLOR=#0000ff]# first digit of number [/color]

  [COLOR=#804040][b]if[/b][/color] (([COLOR=#008080]$field[/color][[COLOR=#ff00ff]0[/color]] [COLOR=#804040][b]eq[/b][/color] [COLOR=#ff00ff]"[/color][COLOR=#ff00ff]H[/color][COLOR=#ff00ff]"[/color])&&([COLOR=#008080]$field[/color][[COLOR=#ff00ff]1[/color]] == [COLOR=#ff00ff]"[/color][COLOR=#ff00ff]0000[/color][COLOR=#ff00ff]"[/color])){    
    [COLOR=#804040][b]if[/b][/color] ([COLOR=#008080]$numb[/color] == [COLOR=#ff00ff]1[/color]) {
      [COLOR=#0000ff]# PO number starts with a 1[/color]
      [COLOR=#008080]$field[/color][[COLOR=#ff00ff]1[/color]] = [COLOR=#ff00ff]"[/color][COLOR=#ff00ff]0120[/color][COLOR=#ff00ff]"[/color];
    }
    [COLOR=#804040][b]elsif[/b][/color] ([COLOR=#008080]$numb[/color] == [COLOR=#ff00ff]7[/color]) {
      [COLOR=#0000ff]# PO number starts with a 7[/color]
      [COLOR=#008080]$field[/color][[COLOR=#ff00ff]1[/color]] = [COLOR=#ff00ff]"[/color][COLOR=#ff00ff]0710[/color][COLOR=#ff00ff]"[/color];
    }         
    [COLOR=#804040][b]elsif[/b][/color] ([COLOR=#008080]$numb[/color] = [COLOR=#ff00ff]8[/color])   {
      [COLOR=#0000ff]# PO number starts with a 8 [/color]
      [COLOR=#008080]$field[/color][[COLOR=#ff00ff]1[/color]] = [COLOR=#ff00ff]"[/color][COLOR=#ff00ff]0800[/color][COLOR=#ff00ff]"[/color];
    }    
  }
  [COLOR=#0000ff]#print "\@field = @field\n";[/color]
  [COLOR=#0000ff]# create new line[/color]
  [COLOR=#804040][b]my[/b][/color] [COLOR=#008080]$newline[/color] = [COLOR=#804040][b]join[/b][/color]([COLOR=#ff00ff]'[/color][COLOR=#ff00ff],[/color][COLOR=#ff00ff]'[/color], [COLOR=#008080]@field[/color]);
  [COLOR=#0000ff]#print "\$newline='$newline'\n";[/color]
  [COLOR=#804040][b]print[/b][/color] [COLOR=#008080]MyOutFile[/color] [COLOR=#ff00ff]"[/color][COLOR=#008080]$newline[/color][COLOR=#6a5acd]\n[/color][COLOR=#ff00ff]"[/color];
}

After running the above script

Code:

C:\Users\Roman\Work>perl jcarrot.pl

you get this file
jcarrot_out.txt

Code:

H,0120,   514659,GHXPCCONNECT810,45066599,,,,,,1533864,,,,,,,,20090529,,,,622.60
D,0000,   514659,GHXPCCONNECT810,45066599,,1,,,,1533864,,,,,,,,,,,,,,,,,,,,,,,,, 
H,0710,   514659,GHXPCCONNECT810,45066599,,,,,,78910,,,,,,,,20090529,,,,622.60
H,0800,   514659,GHXPCCONNECT810,45066599,,,,,,89123,,,,,,,,20090529,,,,622.60

I hope it helps you a little bit.

Roman

brigmar · Jun 3, 2009

mikron has coded the solution (including tidying up the logic and using substr() instead of m//).

My only alteration to his code would be to treat the values as strings and use the 'eq' comparator as opposed to '==', but for our trivial example, it makes no difference.

Whilst it is possible to do 'in-place' editing of a file, it is usually more concise to have an input file and an output file.

jcarrott · Jun 3, 2009

Pleasee start by saying I thanked both of you for the great help.

I had been working on the code using the tips from brigmar. I then changed some of my code using the solution from mikrom.

This is my new code.

open(IN, "D:\\EDI\\810\\ma540csv") or die 'Could not open file for reading';

open(OUT, ">D:\\EDI\\810\\ma540csv.txt") or die 'Could not open file for writing';

foreach $line (<IN>)
{
@field = split(/\,/, $line);
$numb = substr($field[10],0,1); # first digit of number

if (($field[0] eq "H")&&($field[1] == "0000"))
{
if ($numb == 1) # PO number starts with a 1
{
$line =~ s/0000/0120/;
print OUT $line;
}
elsif ($numb == 7) # PO number starts with a 7
{
$line =~ s/0000/0710/;
print OUT $line;
}
elsif ($numb == 8) # PO number starts with a 8
{
$line =~ s/0000/0800/;
print OUT $line;
}
}
else
{
print OUT $line;
}
}
close(IN);
close(OUT);

unlink('D:\EDI\810\ma540csv');

use File::Copy;

$oldfile = 'D:\EDI\810\ma540csv';
$newfile = 'D:\EDI\810\ma540csv.txt';

copy ($newfile, $oldfile) or die "File cannot be copied: $!";

I have to get the new file (ma540csv.txt) copied to the old name (ma540csv). The unlink works to delete the old file, but the copy did not work?

Do you have any ideas?

mikrom · Jun 3, 2009

To execute system command like delete or copy, you can use the function system().
Here is my previous example I improved

Code:

[COLOR=#804040][b]use strict[/b][/color];
[COLOR=#804040][b]use warnings[/b][/color];

[COLOR=#804040][b]my[/b][/color] [COLOR=#008080]$oldfile[/color] = [COLOR=#ff00ff]"[/color][COLOR=#ff00ff]jcarrot_in.txt[/color][COLOR=#ff00ff]"[/color];
[COLOR=#804040][b]my[/b][/color] [COLOR=#008080]$newfile[/color] = [COLOR=#ff00ff]"[/color][COLOR=#ff00ff]jcarrot_out.txt[/color][COLOR=#ff00ff]"[/color];

[COLOR=#804040][b]open[/b][/color]([COLOR=#008080]MyInFile[/color], [COLOR=#ff00ff]"[/color][COLOR=#008080]$oldfile[/color][COLOR=#ff00ff]"[/color]) 
[COLOR=#804040][b]or[/b][/color] [COLOR=#804040][b]die[/b][/color] [COLOR=#ff00ff]'[/color][COLOR=#ff00ff]Could not open file for reading[/color][COLOR=#ff00ff]'[/color];

[COLOR=#804040][b]open[/b][/color]([COLOR=#008080]MyOutFile[/color], [COLOR=#ff00ff]"[/color][COLOR=#ff00ff]>[/color][COLOR=#008080]$newfile[/color][COLOR=#ff00ff]"[/color]) 
[COLOR=#804040][b]or[/b][/color] [COLOR=#804040][b]die[/b][/color] [COLOR=#ff00ff]'[/color][COLOR=#ff00ff]Could not open file for writing[/color][COLOR=#ff00ff]'[/color];

[COLOR=#804040][b]while[/b][/color] ([COLOR=#804040][b]my[/b][/color] [COLOR=#008080]$line[/color]=[COLOR=#008080]<MyInFile>[/color]){
  [COLOR=#804040][b]chomp[/b][/color]([COLOR=#008080]$line[/color]);
  [COLOR=#0000ff]#print "\$line='$line'\n";[/color]
  [COLOR=#804040][b]my[/b][/color] [COLOR=#008080]@field[/color] = [COLOR=#804040][b]split[/b][/color]([COLOR=#804040][b]/[/b][/color][COLOR=#ff00ff],[/color][COLOR=#804040][b]/[/b][/color], [COLOR=#008080]$line[/color]);
  [COLOR=#0000ff]#print "\@field = @field\n";[/color]
  [COLOR=#804040][b]my[/b][/color] [COLOR=#008080]$numb[/color] = [COLOR=#804040][b]substr[/b][/color]([COLOR=#008080]$field[/color][[COLOR=#ff00ff]10[/color]],[COLOR=#ff00ff]0[/color],[COLOR=#ff00ff]1[/color]); [COLOR=#0000ff]# first digit of number [/color]

  [COLOR=#804040][b]if[/b][/color] (([COLOR=#008080]$field[/color][[COLOR=#ff00ff]0[/color]] [COLOR=#804040][b]eq[/b][/color] [COLOR=#ff00ff]"[/color][COLOR=#ff00ff]H[/color][COLOR=#ff00ff]"[/color])&&([COLOR=#008080]$field[/color][[COLOR=#ff00ff]1[/color]] == [COLOR=#ff00ff]"[/color][COLOR=#ff00ff]0000[/color][COLOR=#ff00ff]"[/color])){    
    [COLOR=#804040][b]if[/b][/color] ([COLOR=#008080]$numb[/color] == [COLOR=#ff00ff]1[/color]) {
      [COLOR=#0000ff]# PO number starts with a 1[/color]
      [COLOR=#008080]$field[/color][[COLOR=#ff00ff]1[/color]] = [COLOR=#ff00ff]"[/color][COLOR=#ff00ff]0120[/color][COLOR=#ff00ff]"[/color];
    }
    [COLOR=#804040][b]elsif[/b][/color] ([COLOR=#008080]$numb[/color] == [COLOR=#ff00ff]7[/color]) {
      [COLOR=#0000ff]# PO number starts with a 7[/color]
      [COLOR=#008080]$field[/color][[COLOR=#ff00ff]1[/color]] = [COLOR=#ff00ff]"[/color][COLOR=#ff00ff]0710[/color][COLOR=#ff00ff]"[/color];
    }         
    [COLOR=#804040][b]elsif[/b][/color] ([COLOR=#008080]$numb[/color] == [COLOR=#ff00ff]8[/color])  {
      [COLOR=#0000ff]# PO number starts with a 8 [/color]
      [COLOR=#008080]$field[/color][[COLOR=#ff00ff]1[/color]] = [COLOR=#ff00ff]"[/color][COLOR=#ff00ff]0800[/color][COLOR=#ff00ff]"[/color];
    }    
  }
  [COLOR=#0000ff]#print "\@field = @field\n";[/color]
  [COLOR=#0000ff]# create new line[/color]
  [COLOR=#804040][b]my[/b][/color] [COLOR=#008080]$newline[/color] = [COLOR=#804040][b]join[/b][/color]([COLOR=#ff00ff]'[/color][COLOR=#ff00ff],[/color][COLOR=#ff00ff]'[/color], [COLOR=#008080]@field[/color]);
  [COLOR=#0000ff]#print "\$newline='$newline'\n";[/color]
  [COLOR=#804040][b]print[/b][/color] [COLOR=#008080]MyOutFile[/color] [COLOR=#ff00ff]"[/color][COLOR=#008080]$newline[/color][COLOR=#6a5acd]\n[/color][COLOR=#ff00ff]"[/color];
}
[COLOR=#0000ff]# close files[/color]
[COLOR=#804040][b]close[/b][/color]([COLOR=#008080]MyInFile[/color]);
[COLOR=#804040][b]close[/b][/color]([COLOR=#008080]MyOutFile[/color]);

[COLOR=#0000ff]# delete oldfile[/color]
[COLOR=#804040][b]my[/b][/color] [COLOR=#008080]$rc[/color]=[COLOR=#804040][b]system[/b][/color]([COLOR=#ff00ff]"[/color][COLOR=#ff00ff]del [/color][COLOR=#008080]$oldfile[/color][COLOR=#ff00ff]"[/color]);
[COLOR=#0000ff]# copy newfile to oldfile[/color]
[COLOR=#804040][b]if[/b][/color] ([COLOR=#008080]$rc[/color]==[COLOR=#ff00ff]0[/color]) {
  [COLOR=#008080]$rc[/color]=[COLOR=#804040][b]system[/b][/color]([COLOR=#ff00ff]"[/color][COLOR=#ff00ff]copy [/color][COLOR=#008080]$newfile[/color][COLOR=#ff00ff] [/color][COLOR=#008080]$oldfile[/color][COLOR=#ff00ff]"[/color]);
}
[COLOR=#0000ff]# delete newfile so only oldfile remains[/color]
[COLOR=#008080]$rc[/color]=[COLOR=#804040][b]system[/b][/color]([COLOR=#ff00ff]"[/color][COLOR=#ff00ff]del [/color][COLOR=#008080]$newfile[/color][COLOR=#ff00ff]"[/color]);

mikrom · Jun 3, 2009

jcarrott,

And don't forget to use

Code:

use strict;
use warnings;

It's very useful, e.g. in my 1.example I had this error at

Code:

...
elsif ([COLOR=red]$numb = 8[/color]) {      
...
}

But after I used

Code:

use warnings;

I got the warning:
Found = in conditional, should be == at jcarrot.pl line 29. and so I could correct the above error in 2.example to

Code:

...
elsif ([COLOR=green]$numb == 8[/color]) {      
...
}

jcarrott · Jun 4, 2009

Thank you very much this works great.

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parsing a perl string 2

jcarrott

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brigmar

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jcarrott

Programmer

mikrom

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brigmar

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jcarrott

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mikrom

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mikrom

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jcarrott

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