Question

I’ve been working on this for a bit, but my regex is weak.

I need to check to see if a number is a whole number (single digit) and append a “.001” to it if so. The problem is, it’s in the middle of a line with values separated by commas.

MATERIALS,1,1,9999;1 4PL1 PB_Mel,,1,6,0.173,0.173,0.375,0,0.375,0,0,0,0,2,0,1,1

Needs to be

MATERIALS,1,1,9999;1 4PL1 PB_Mel,,1.001,6,0.173,0.173,0.375,0,0.375,0,0,0,0,2,0,1,1

1. The line must start with “MATERIALS”.
2. There are more than one MATERIALS lines.
3. The value will always be after 5 commas.

I was trying something like this to even replace the number, but I don’t think the approach is quite right:

$stripped = preg_replace('/(MATERIALS)(,.*?){4}(,\d+?),/', '\2,', $stripped);

I tried going through a preg_match_all > for > if process, to at least get the conditional working, but I still have to replace the lines.

EDIT: I forgot the preg_match_all line that proceeded the loop.

preg_match_all('/MATERIALS.*/', $stripped, $materialsLines);
for($i=0;$i<sizeof($materialsLines[0]);$i++) {
            $section = explode(",",$materialsLines[0][$i]);
            if (strlen($section[5]) == 1) {
                $section[5] .= ".001";
            }
            $materialsLines[0][$i] = implode(",",$section);
        }

Answer 1

Why use a regex? You can simply explode the string on comma, check the value in [5], fix it and join the string back together.

$str = 'MATERIALS,1,1,9999;1 4PL1 PB_Mel,,1,6,0.173,0.173,0.375,0,0.375,0,0,0,0,2,0,1,1';
$line = explode(',',$str);
if(strpos($line[5],'.')===false){
    $line[5] .= '.001';
}
$str = implode(',', $line);

http://codepad.org/g4r3pLpS

If reading multiple lines from a file:

$file = file("someFile.txt");
foreach($file as $key=>$line){
    $line = explode(',', $line);
    if($line[0] == 'MATERIALS'){
        if(strpos($line[5],'.')!==false){
            $line[5] .= '.001';
            $file[$key] = implode(',', $line);
        }
    }
}
file_put_contents("someFile2.txt", implode('',$file));

if for some reason you HAVE to use a regex, this worked for me:

$str = 'MATERIALS,1,1,9999;1 4PL1 PB_Mel,,1,6,0.173,0.173,0.375,0,0.375,0,0,0,0,2,0,1,1
MATERIALS,1,1,9999;1 4PL1 PB_Mel,,1.101,6,0.173,0.173,0.375,0,0.375,0,0,0,0,2,0,1,1
FOO,1,1,9999;1 4PL1 PB_Mel,,1.1,6,0.173,0.173,0.375,0,0.375,0,0,0,0,2,0,1,1
BLAH,1,1,9999;1 4PL1 PB_Mel,,1,6,0.173,0.173,0.375,0,0.375,0,0,0,0,2,0,1,1
MATERIALS,1,1,9999;1 4PL1 PB_Mel,,567,6,0.173,0.173,0.375,0,0.375,0,0,0,0,2,0,1,1';

$str = preg_replace('/^(MATERIALS(,[^,]*){4},)(\d+),/m', '$1$3.001,', $str);
echo $str;

http://codepad.org/l7FfJlDe