PHP How to Convert Array to CSV File or String

Use fputcsv() to write an array as a CSV line to a file, or use implode(",", $array) to convert an array to a CSV string in PHP.

Examples

Input["apple", "banana", "cherry"]

Outputapple,banana,cherry

Input[["name", "age"], ["John", 30], ["Jane", 25]]

Outputname,age John,30 Jane,25

Input[]

Output

How to Think About It

To convert an array to CSV in PHP, decide if you want a CSV string or a CSV file. For a string, join array elements with commas using implode. For a file, open it and write each array row as a CSV line using fputcsv which handles commas and quotes properly.

Algorithm

1

Get the input array.

2

If writing to a file, open the file in write mode.

3

For each row in the array, write it as a CSV line using <code>fputcsv</code>.

4

If creating a string, join array elements with commas using <code>implode</code>.

5

Close the file if opened.

6

Return or output the CSV string or file.

Code

php

<?php
$array = ["apple", "banana", "cherry"];
// Convert array to CSV string
$csvString = implode(",", $array);
echo $csvString;

// Convert 2D array to CSV file
$data = [["name", "age"], ["John", 30], ["Jane", 25]];
$file = fopen('output.csv', 'w');
foreach ($data as $row) {
    fputcsv($file, $row);
}
fclose($file);
?>

Output

apple,banana,cherry

Dry Run

Let's trace converting ["apple", "banana", "cherry"] to CSV string using implode.

1

Input array

["apple", "banana", "cherry"]

2

Join elements

"apple" + "," + "banana" + "," + "cherry"

3

Output CSV string

"apple,banana,cherry"

Step	Action	Result
1	Input array	["apple", "banana", "cherry"]
2	Join with commas	"apple,banana,cherry"
3	Output string	apple,banana,cherry

Why This Works

Step 1: Using implode for CSV string

implode joins array elements with commas to create a CSV line as a string.

Step 2: Using fputcsv for CSV file

fputcsv writes an array as a properly formatted CSV line to a file, handling commas and quotes automatically.

Step 3: File handling

Open the file with fopen, write lines with fputcsv, then close it with fclose to save changes.

Alternative Approaches

Manual string building

php

<?php
$array = ["apple", "banana", "cherry"];
$csv = '';
foreach ($array as $item) {
    $csv .= '"' . str_replace('"', '""', $item) . '",';
}
$csv = rtrim($csv, ',');
echo $csv;
?>

Manually adds quotes and escapes quotes inside values but is more error-prone than fputcsv.

Using output buffering

php

<?php
$data = [["name", "age"], ["John", 30], ["Jane", 25]];
ob_start();
$file = fopen('php://output', 'w');
foreach ($data as $row) {
    fputcsv($file, $row);
}
fclose($file);
$csvString = ob_get_clean();
echo $csvString;
?>

Captures CSV output as a string without writing to a physical file.

Complexity: O(n) time, O(n) space

Time Complexity

The code loops through each element or row once, so time grows linearly with array size.

Space Complexity

Extra space depends on the output string or file buffer, proportional to input size.

Which Approach is Fastest?

implode is fastest for simple 1D arrays to string; fputcsv is best for files and complex data.

Approach	Time	Space	Best For
implode	O(n)	O(n)	Simple 1D array to CSV string
fputcsv	O(n)	O(n)	Writing arrays to CSV files with proper formatting
Manual string building	O(n)	O(n)	Custom formatting but error-prone