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Practical Guide to Fixing PHP Error: Unexpected '

M66 2025-06-24

How to Fix the PHP Error: “Unexpected ']' Symbol”?

In PHP development, encountering various error messages is common. Among them, the “unexpected ']' symbol” is a frequent yet confusing syntax error. This article will analyze the typical causes of this error and guide you through specific code examples on how to quickly diagnose and fix it.

Error Message

When an “unexpected ']' symbol” error occurs in PHP code, you typically see the following message:

Parse error: syntax error, unexpected ']' in filename.php on line X

Here, “filename.php” is the file where the error happened, and “X” is the line number.

Cause Analysis

This error is mostly caused by improper array structure, mainly including:

  • Invalid or syntactically incorrect array indexes;
  • Incorrect key-value pair syntax in arrays.

Solutions

1. Invalid or Syntax Error in Array Index

This type of error often results from small details in array definition, such as an extra comma or wrong index usage.

Step 1: Check if there is an extra comma after the last array element.

$names = array(
    "John",
    "Michael",
    "David",
    "Sarah",
);

In the example above, the trailing comma after the last element may cause the “unexpected ']' symbol” error.

The correct way is to remove the extra comma:

$names = array(
    "John",
    "Michael",
    "David",
    "Sarah"
);

Step 2: Confirm the array indexes are valid; variables cannot be used directly as indexes.

$name = "John";
$age = 30;
$person = [
    $name,
    $age,
];

Using variables as indexes like above may trigger this error. The solution is to use explicit numeric indexes:

$person = [
    0 => $name,
    1 => $age,
];

2. Incorrect Key-Value Pair Syntax

Key-value pairs must use the key => value syntax and cannot use colons or other symbols.

Incorrect example:

$person = [
    "name": "John",
    "age" => 30,
];

Using a colon instead of => causes a syntax error that triggers the unexpected symbol error.

Correct syntax:

$person = [
    "name" => "John",
    "age" => 30,
];

Note: Keys must be valid strings or defined constants. Using undefined constants as keys will cause errors.

define("PI", 3.14);
$person = [
    PI => "John",  // Error if PI is not defined
    "age" => 30,
];

If the constant is not defined, it will cause this error. The proper way is:

define("PI", 3.14);
$person = [
    "PI" => "John",
    "age" => 30,
];

Summary

When facing the PHP error “unexpected ']' symbol,” carefully check the array syntax, ensure indexes and key-value pairs are correctly written without extra characters. Careful inspection usually helps quickly locate and fix this common issue.

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