PHP to delete lines within text file beginning with 0 or a negative number
Thank you for taking the time to read this and I will appreciate every single response no mater the quality of content. :)
Using php, I'm trying to create a script which will delete several lines within a text file (.txt) if required, based upon whether the line starts with a 0 or a negative number. Each line within the file will always start with a number, and I need to erase all the neutral and/or negative numbers.
The main part I'm struggling with is that the content within the text file isn't static (e.g. contain x number of lines/words etc.) Infact, it is automatically updated every 5 minutes with several lines. Therefore, I'd like all the lines containing a neutral or negative number to be removed.
The text file follows the structure:
-29 aullah1
0 name
4 username
4 user
6 player
If possible, I'd like Line 1 and 2 removed, since it begins with a neutral/negative number. At points, there maybe times when there are more than two neutral/negative numbers.
All assistance is appreciated and I look forward to your replies; thank you. :) If I didn't explain anything clearly and/or you'd like me to explain in more detail开发者_开发技巧, please reply. :)
Thank you.
Example:
$file = file("mytextfile.txt");
$newLines = array();
foreach ($file as $line)
if (preg_match("/^(-\d+|0)/", $line) === 0)
$newLines[] = chop($line);
$newFile = implode("\n", $newLines);
file_put_contents("mytextfile.txt", $newFile);
It is important that you chop()
the newline character off of the end of the line so you don't end up with empty space. Tested successfully.
Something on these lines i guess, it is untested.
$newContent = "";
$lines = explode("\n" , $content);
foreach($lines as $line){
$fChar = substr($line , 0 , 1);
if($fChar == "0" || $fChar == "-") continue;
else $newContent .= $line."\n";
}
If the file is big, its better to read it line by line as:
$fh_r = fopen("input.txt", "r"); // open file to read.
$fh_w = fopen("output.txt", "w"); // open file to write.
while (!feof($fh_r)) { // loop till lines are left in the input file.
$buffer = fgets($fh_r); // read input file line by line.
// if line begins with num other than 0 or -ve num write it.
if(!preg_match('/^(0|-\d+)\b/',$buffer)) {
fwrite($fh_w,$buffer);
}
}
fclose($fh_r);
fclose($fh_w);
Note: Err checking not included.
file_put_contents($newfile,
implode(
preg_grep('~^[1-9]~',
file($oldfile))));
php is not particularly elegant, but still...
Load whole line into variable trim it and then check if first letter is - or 0.
$newContent = "";
$lines = explode("\n" , $content);
foreach($lines as $line){
$fChar = $line[0];
if(!($fChar == '0' || $fChar == '-'))
$newContent .= $line."\n";
}
I changed malik's code for better performance and quality.
Here's another way:
class FileCleaner extends FilterIterator
{
public function __construct($srcFile)
{
parent::__construct(new ArrayIterator(file($srcFile)));
}
public function accept()
{
list($num) = explode(' ', parent::current(), 2);
return ($num > 0);
}
public function write($file)
{
file_put_contents($file, implode('', iterator_to_array($this)));
}
}
Usage:
$filtered = new FileCleaner($src_file);
$filtered->write($new_file);
Logic and methods can be added to the class for other stuff, such as sorting, finding the highest number, converting to a sane storage method such as csv, etc. And, of course, error checking.
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