File loop in PHP
I wrote some code to create a text file just once each time I execute the php file. Its idea is to check all existing files with a specific name then create a text file with the previous name +1
For example, if there is a file called filetext0.txt
, my code will create a file called filetext1.txt
and so on...
Please help me to find the error in my code:
<?php
for ($i=0; $i=1000; $i=$i+1)
{
$handle = fopen("filetext".$i.".txt","r");
if ($handle) {
fclose($handle);
$s=$i+1
$handlex = fopen("filetext".$s.".txt","w+开发者_Go百科");
fclose($handlex);
break
}
}
?>
First of all you should use file_exists in the first step.
Then, your problem are missing semi-colon ';' at the end of lines. Check the error messages on your web pages next time ;)
And finally, your code create a file each file it found, not only one.
I'll suggest this code :
$i = 0;
while(true) {
$filename = "filetext".$i.".txt";
if(! file_exists($filename)) {
touch($filename);
break;
}
$i++
}
You do not have to open each and ever file to check if it exists. You should use PHP's directory functions.
// the maximum number
$maxnum = 0;
$d = dir(".");
while (false !== ($entry = $d->read())) {
if (preg_match ('/filetext([0-9]+)\.txt/', $entry, $matches)) {
if ($matches[1] > $maxnum) {
$maxnum = $matches[1];
}
}
}
$d->close();
echo ("The biggest number is: " . $maxnum);
// increment maxnum
$maxnum++;
// creating the file
touch ("filetext" . $maxnum . ".txt");
You need a ;
after each statement.
$fileNames = glob('filetext*.txt');
$latestNumber = -1;
foreach($fileNames as $fileName) {
list($fileNumber) = sscanf($fileName,'filetext%d.txt');
$latestNumber = max($latestNumber,$fileNumber);
}
if ($fileNumber > -1) {
$fileName = 'filetext'.($fileNumber+1).'.txt';
touch($fileName);
}
Leaving aside the syntax errors, the algorithm you are using does not scale well. A better solution would be a searching method something like:
function find_next($stub)
{
$increment=1000; // depending on number of files
$offset=0;
for ($x=0; $x<500; $x++) {
$offset+=$increment;
if (file_exists($stub . $offset)) {
if ($increment<0) {
$increment=-1*((integer)($increment/2) ? $increment/2 : 1;
}
} else {
if (file_exists($stub . ($offset-1)) {
return $offset;
}
if ($increment>0) {
$increment=-1*((integer)($increment/2) ? $increment/2 : 1;
}
}
}
return false; // too many files!
}
(NB I'm just typing this stuff - the above may be a bit buggy).
But it'd be a lot better to store a sequence number and increment it each time you add a file.
However do beware that storing transactional data for a multi-user system using files with PHP is a very bad idea.
Yes used file_exists function to find next name for the file.
The above code missed the brace in if condition.
here code for your problem
$i = 0;
while(true) {
$myfile = "myfile".$i.".txt";
if(!file_exists($myfile)) {
$fh = fopen($myfile, 'w');
fclose($fh);
break;
}
$i++;
}
精彩评论