What’s the Difference Between PHP's file() and file_get_contents() Functions? How to Choose the More Suitable One?

gitbox 2025-09-12

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What’s the Difference Between PHP's file() and file_get_contents() Functions? How to Choose the More Suitable One?

// Introduction
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In PHP, reading file content is a very common operation. The file() and file_get_contents() functions are two commonly used functions for reading files, but they differ in their return values, use cases, and performance. This article will compare the differences between them in detail and provide suggestions for selection.

// 1. file() function
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1. file() Function

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The file() function reads the entire file into an array, with each line returned as an element of the array:

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\n"</span></span><span>;<br>
</span><span><span>echo</span></span><span> </span><span><span>"$lines = file('example.txt');\n"</span></span><span>;<br>
</span><span><span>echo</span></span><span> </span><span><span>"foreach ($lines as $line) {\n"</span></span><span>;<br>
</span><span><span>echo</span></span><span> </span><span><span>"    echo $line;\n"</span></span><span>;<br>
</span><span><span>echo</span></span><span> </span><span><span>"}\n"</span></span><span>;<br>
</span><span><span>echo</span></span><span> </span><span><span>"

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Features:

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Returns an array, with each line as an element.
Suitable for processing file content line by line.
Can easily be combined with loops to process the file.

// 2. file_get_contents() function
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2. file_get_contents() Function

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The file_get_contents() function reads the entire file into a string:

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\n"</span></span><span>;<br>
</span><span><span>echo</span></span><span> </span><span><span>"$content = file_get_contents('example.txt');\n"</span></span><span>;<br>
</span><span><span>echo</span></span><span> </span><span><span>"echo $content;\n"</span></span><span>;<br>
</span><span><span>echo</span></span><span> </span><span><span>"

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Features:

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Returns the entire content of the file as a string.
Suitable for reading the entire file at once and processing the content as a whole, such as searching or replacing.
More memory-efficient than file() when not processing line by line.

// 3. Comparison Summary
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3. Comparison Summary

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Feature	file()	file_get_contents()
Return Type	Array, each line as an element	String, entire file content
Use Case	Processing file content line by line	Reading the entire file at once, processing the content as a whole
Memory Usage	May consume more memory for large files when processing line by line	May consume more memory when reading large files at once
Common Use Cases	Reading log files, configuration files line by line	Reading templates, configuration text, API responses

// 4. Selection Suggestions
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4. Selection Suggestions

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Which function to choose depends on your requirements:

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If you need to process the file line by line, such as reading log files or processing CSV files, file() is more convenient.
If you only need to retrieve the entire file content at once, such as reading HTML templates or remote text data, file_get_contents() is more straightforward.
Be mindful of memory usage for large files; you may want to consider using fopen() combined with fgets() for line-by-line reading if needed.

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In conclusion, file() is better suited for line-by-line processing, while file_get_contents() is more appropriate for retrieving the entire content at once. Choosing the right function based on your actual needs can make your PHP file operations more efficient.

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