PHP explode() Function

What You’ll Learn

The explode() function splits a string into an array of pieces wherever a delimiter appears. It is one of the most-used PHP functions for parsing CSV data, URLs, tags, and any text separated by a known character or substring.

Definition and Usage

In PHP, explode() breaks a string at every occurrence of a separator and returns the pieces as an indexed array. The separator itself is removed from the results. If the separator is not found, you get a one-element array containing the original string.

📝 Syntax

The explode() function accepts a separator, a string, and an optional limit:

array explode(string $separator, string $string, int $limit = PHP_INT_MAX)

Parameters

• $separator — the boundary string to split on (e.g. ",", " ", "|"). Cannot be empty in PHP 8+.
• $string — the input string to split.
• $limit (optional) — maximum number of elements returned. Positive: last element holds the remainder. Negative: excludes elements from the end.

Return Value

Returns an array of strings. An empty input string returns [""] (one empty element), not an empty array.

Examples Gallery

Run these examples in PHP 7+. Each demonstrates a common pattern beginners encounter with explode().

<?php
$string = "apple,orange,banana";
$fruits = explode(",", $string);

print_r($fruits);

foreach ($fruits as $fruit) {
    echo "- $fruit\n";
}
?>

Array
(
    [0] => apple
    [1] => orange
    [2] => banana
)
- apple
- orange
- banana

<?php
$sentence = "Hello World";
$parts    = explode(" ", $sentence, 2);

print_r($parts);

$str = "one|two|three|four";
print_r(explode("|", $str, 2));
?>

Array
(
    [0] => Hello
    [1] => World
)
Array
(
    [0] => one
    [1] => two|three|four
)

<?php
$str = "one|two|three|four";

echo "No limit:\n";
print_r(explode("|", $str));

echo "Limit -1 (drop last element):\n";
print_r(explode("|", $str, -1));

echo "Delimiter not found:\n";
print_r(explode(",", "hello"));
?>

No limit:
Array
(
    [0] => one
    [1] => two
    [2] => three
    [3] => four
)
Limit -1 (drop last element):
Array
(
    [0] => one
    [1] => two
    [2] => three
)
Delimiter not found:
Array
(
    [0] => hello
)

<?php
// Split a URL path into segments
$path    = "articles/42/show";
$segments = explode("/", $path);
echo "Segments: " . implode(" | ", $segments) . "\n";

// Parse key=value pairs from a query string
$query   = "name=Alice&role=editor&active=1";
$pairs   = explode("&", $query);

foreach ($pairs as $pair) {
    [$key, $value] = explode("=", $pair, 2);
    echo "$key => $value\n";
}
?>

Segments: articles | 42 | show
name => Alice
role => editor
active => 1

<?php
$original = "red,green,blue,yellow";
$delimiter = ",";

$parts   = explode($delimiter, $original);
$rebuilt = implode($delimiter, $parts);

echo "Original: $original\n";
echo "Parts:    " . count($parts) . " items\n";
echo "Rebuilt:  $rebuilt\n";
echo "Match:    " . ($rebuilt === $original ? "yes\n" : "no\n");

// Change delimiter on rebuild
echo "Pipe-delimited: " . implode("|", $parts) . "\n";
?>

Original: red,green,blue,yellow
Parts:    4 items
Rebuilt:  red,green,blue,yellow
Match:    yes
Pipe-delimited: red|green|blue|yellow

🚀 Common Use Cases

• CSV and list parsing — split comma-, pipe-, or tab-separated values into arrays.
• URL and path segments — break /articles/42/show into route parts.
• Query string handling — split key=value pairs (use parse_str() for full URLs).
• Tag and keyword lists — convert php,html,css into individual tags.
• Log file parsing — split lines on delimiters for analysis.

📝 Notes

• Argument order is explode($separator, $string)—separator first, always.
• An empty separator throws ValueError in PHP 8+ (use str_split() for character arrays).
• An empty input string returns [""], not an empty array.
• Leading or trailing separators produce empty string elements at the start or end.
• For complex patterns (regex), use preg_split() instead of explode().

💡 Best Practices