PHP file_put_contents() Function: Syntax, Parameters, and Usage Examples

The PHP function file_put_contents() is used to write data to a file. Its basic usage is to write the specified data to the specified file. The function can accept multiple parameters, including filename, data, mode, and context.

Function Syntax:

<code>file_put_contents(filename, data, mode, context)</code>

Parameter Description:

filename : required. The name of the file to write to.

data : required. The data to write; can be a string, array, or object.

mode : optional. Write mode, default 0 (overwrite). Use FILE_APPEND to append data.

context : optional. Stream context for additional options such as file permissions.

Function Usage Examples:

1. Write a string to a file:

<code>$data = "Hello, World!";
file_put_contents("file.txt", $data);
</code>

The above code writes the string "Hello, World!" to file.txt . If the file does not exist, it is created; if it exists, its contents are overwritten.

2. Append a string to the end of a file:

<code>$data = "Hello, World!";
file_put_contents("file.txt", $data, FILE_APPEND);
</code>

This code appends the string "Hello, World!" to the end of file.txt . If the file does not exist, it is created; otherwise the new data is added after the existing content.

3. Convert an array to JSON and write to a file:

<code>$data = array("name" => "John", "age" => 30);
$jsonData = json_encode($data);
file_put_contents("file.json", $jsonData);
</code>

The array is encoded to a JSON string and written to file.json .

4. Write to a file while setting file permissions:

<code>$data = "Hello, World!";
file_put_contents("file.txt", $data, 0, stream_context_create(array('chmod' => 0644)));
</code>

This writes the string to file.txt and sets the file's permissions to 0644 .

The file_put_contents() function also supports writing via URLs and using additional stream context options; choose the appropriate usage based on your needs.

When using file_put_contents() , ensure the target file and its directory have write permissions; otherwise the operation may fail, and proper error handling should be implemented.

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