Reading Text Files Line-by-Line in PHP | CodeSignal Learn

Reading Text Files Line-by-Line in PHP | CodeSignal Learn

File handling in PHP can be done using the file() function, which reads the entire file into an array, with each element representing a line:

PHP

$lines = file($filePath, FILE_IGNORE_NEW_LINES);

The file() function is called with parameters that specify how the file should be read and how each line should be treated:

$filePath: The path to the file from which to read lines.
FILE_IGNORE_NEW_LINES: This optional parameter prevents PHP from adding a trailing newline character to each array element, which is useful for precise string manipulation.

To iterate over the lines read from the file, use a foreach loop as shown below:

PHP

foreach ($lines as $line) {
    // Process each line
}

In this block, $lines contains each line of the file as an array element, and the foreach loop iterates over the array, allowing you to process or manipulate each line individually.

To read a file line-by-line in PHP, use the file() function and iterate over the results with a foreach loop. Let's see this in action:

PHP

$filePath = 'data.txt';
echo "Reading file line-by-line:\n";

$lines = file($filePath, FILE_IGNORE_NEW_LINES);

foreach ($lines as $line) {
    echo $line . "\n"; // Output each line to the console
}

Here, file($filePath, FILE_IGNORE_NEW_LINES) reads lines from data.txt one-by-one. Each line is stored in the $line variable and then printed to the console.

Imagine needing to process a set of numbers stored in a file — reading each integer and calculating their sum. This is a practical task you can accomplish using the file() function with ease.

Assume numbers.txt contains:

text

The following PHP code reads integers from this file and calculates their sum:

PHP

<?php

$filePath = 'numbers.txt';
$totalSum = 0;

$lines = file($filePath, FILE_IGNORE_NEW_LINES);

foreach ($lines as $line) {
    if (is_numeric($line)) {
        $totalSum += (int) $line; // Add the integer to totalSum
    }
}

echo "The sum of the numbers is: " . $totalSum . "\n";

?>

Reading Numbers: Each line is checked to be numeric and parsed to an integer.
Calculating Sum: The integers are added together in the $totalSum variable.

After executing this code, the output displays the total sum of the numbers:

text

The sum of the numbers is: 100