Both r+ and w+ can read and write to a file. However, r+ doesn’t delete the content of the file and doesn’t create a new file if such file doesn’t exist, whereas w+ deletes the content of the file and creates it if it doesn’t exist.
Yes, you can do that easily with SplFileObject::seek $file = new SplFileObject(‘filename.txt’); $file->seek(1000); for($i = 0; !$file->eof() && $i < 1000; $i++) { echo $file->current(); $file->next(); } This is a method from the SeekableIterator interface and not to be confused with fseek. And because SplFileObject is iterable you can do it even easier with a … Read more
The proper thing to do is check errno when fopen returns NULL. I’m going to guess that your problem is that you’re trying to write to a filesystem that doesn’t allow \n in filenames, but it could be a permissions issue as well.
For a large file, reading all the lines into an array with file() is a bit wasteful. Here’s how you could read the file and maintain a buffer of the last 5 lines: $lines=array(); $fp = fopen(“file.txt”, “r”); while(!feof($fp)) { $line = fgets($fp, 4096); array_push($lines, $line); if (count($lines)>5) array_shift($lines); } fclose($fp); You could optimize this … Read more
As long as your program is running, if you keep opening files without closing them, the most likely result is that you will run out of file descriptors/handles available for your process, and attempting to open more files will fail eventually. On Windows, this can also prevent other processes from opening or deleting the files … Read more
Much simpler: <?php if( strpos(file_get_contents(“./uuids.txt”),$_GET[‘id’]) !== false) { // do stuff } ?> In response to comments on memory usage: <?php if( exec(‘grep ‘.escapeshellarg($_GET[‘id’]).’ ./uuids.txt’)) { // do stuff } ?>
It looks like Microsoft has deprecated lots of calls which use buffers to improve code security. However, the solutions they’re providing aren’t portable. Anyway, if you aren’t interested in using the secure version of their calls (like fopen_s), you need to place a definition of _CRT_SECURE_NO_DEPRECATE before your included header files. For example: #define _CRT_SECURE_NO_DEPRECATE … Read more
Replace ‘\n’ with “\n”. The escape sequence is not recognized when you use ‘. See the manual. For the question of how to write line endings, see the note here. Basically, different operating systems have different conventions for line endings. Windows uses “\r\n”, unix based operating systems use “\n”. You should stick to one convention … Read more
Thats because your test for EOF is before you output your last read Try this with the test for EOF as part of the reading process <?php $line_count = 0; $handle = fopen(“item_sets.txt”, “r”); if ($handle) { while (($buffer = fgets($handle, 4096)) !== false) { $trimmed = trim($buffer); echo $trimmed; $line_count++; } } else { … Read more
I would recommend looking at David Beazley’s Generator Tricks for Python, especially Part 5: Processing Infinite Data. It will handle the Python equivalent of a tail -f logfile command in real-time. # follow.py # # Follow a file like tail -f. import time def follow(thefile): thefile.seek(0,2) while True: line = thefile.readline() if not line: time.sleep(0.1) … Read more