In PHP, reading CSV and JSON files serves different purposes and is done using different built-in functions. Here’s a comparison of CSV reading vs JSON reading in PHP, including syntax, performance, and use cases.

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1. Basic Difference

Feature	CSV	JSON
Format	Comma-separated values (plain text)	JavaScript Object Notation (structured)
Structure	Tabular (rows and columns)	Hierarchical (key-value, nested)
Human readable	Yes	Yes
Size	Smaller (usually)	Slightly larger due to syntax
Use case	Spreadsheet-like data	API responses, configs, complex data

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2. How to Read CSV in PHP

$csvFile = fopen("data.csv", "r");
while (($data = fgetcsv($csvFile, 1000, ",")) !== FALSE) {
    print_r($data);
}
fclose($csvFile);

• fopen: Opens the file.
• fgetcsv: Reads one line and parses it into an array.

Best for: flat/tabular data (e.g., Excel exports).

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3. How to Read JSON in PHP

$jsonString = file_get_contents("data.json");
$data = json_decode($jsonString, true);
print_r($data);

• file_get_contents: Reads entire file into a string.
• json_decode: Converts JSON string to PHP array/object.

Best for: structured/nested data (e.g., API responses).

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4. Performance Comparison

Aspect	CSV	JSON
Speed	Faster for very large flat data	Slightly slower due to parsing overhead
Memory usage	Lower	Higher (especially for nested data)
Parse method	Line-by-line	Whole file at once

• CSV is more memory-efficient when processing very large datasets line by line.
• JSON is better for representing complex/nested structures, but uses more memory.

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5. When to Use What

Scenario	Use
Export/import from Excel/spreadsheet	CSV
Working with API responses	JSON
Config or nested data	JSON
Simple table data with no nesting	CSV
Huge files needing line-by-line reading	CSV

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Summary

Feature	CSV	JSON
Format	Flat	Structured/nested
Functions	fopen, fgetcsv	file_get_contents, json_decode
Use case	Tables	Complex data structures
Speed	Faster for big files	Slower but more flexible
Memory	Lower	Higher