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PHP Tutorial · PHP for the Web · Lesson 23 of 38

PHP File Handling

Read, write and append files, and work with CSV.

Reading and writing whole files

file_put_contents() and file_get_contents() are the simplest tools:

Example 1Try it yourself
<?php
$path = sys_get_temp_dir() . "/notes.txt";
file_put_contents($path, "First line\n");
file_put_contents($path, "Second line\n", FILE_APPEND);
echo file_get_contents($path);
$lines = file($path, FILE_IGNORE_NEW_LINES);
echo count($lines), " lines; last: ", end($lines), "\n";
unlink($path);
var_dump(file_exists($path));

Output

First line
Second line
2 lines; last: Second line
bool(false)

Line by line

file() returns an array of lines. For big files, open a handle with fopen() and read with fgets() so you don't load everything into memory.

CSV files

Example 2Try it yourself
<?php
$path = sys_get_temp_dir() . "/orders.csv";
$fh = fopen($path, "w");
fputcsv($fh, ["id", "customer", "total"]);
fputcsv($fh, [1, "Ada", 42.5]);
fputcsv($fh, [2, "Lin, Jr.", 19.99]);
fclose($fh);

$fh = fopen($path, "r");
$header = fgetcsv($fh);
while (($row = fgetcsv($fh)) !== false) {
    $order = array_combine($header, $row);
    echo "#{$order['id']} {$order['customer']}: {$order['total']}\n";
}
fclose($fh);

Output

#1 Ada: 42.5
#2 Lin, Jr.: 19.99

Checking files

file_exists(), is_file(), is_dir(), filesize() and unlink() (delete). Always check whether a file exists before reading it, and never build paths from raw user input.

Test yourself

Which flag makes file_put_contents() add to the end of a file?

  1. FILE_ADD
  2. FILE_APPEND
  3. APPEND_MODE
  4. FILE_END
Show answer

Answer: FILE_APPEND

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