Accessing 2D Array Elements

Part of the Logic & Flow section of Coddy's PHP journey — lesson 28 of 68.

Now that you know how to create 2D arrays, the next step is learning how to retrieve specific values from them. Accessing elements in a 2D array requires two indices: the first for the row and the second for the column, using the syntax $array[row][column].

Here's how you access a specific element in a 2D array:

<?php
$products = [
    ["Laptop", 999.99],
    ["Mouse", 25.50],
    ["Keyboard", 75.00]
];

// Access the price of the first product (Laptop)
echo $products[0][1]; // Outputs: 999.99

// Access the name of the second product (Mouse)
echo $products[1][0]; // Outputs: Mouse
?>

The first index [0] selects the first row (the laptop array), and the second index [1] selects the second element within that row (the price). Think of it as navigating to a specific cell in a spreadsheet by specifying both the row and column.

This double-indexing system allows you to pinpoint exactly which piece of data you want from your grid-like structure, making 2D arrays perfect for organizing related information in rows and columns.

Challenge

Easy

You will receive three inputs: a 2D array of student information in JSON format, a row index, and a column index. Read all three inputs, convert the JSON string to a 2D array, access the element at the specified row and column indices, and print that element.

The 2D array represents students where each inner array contains: [student_name, age, grade]

Input format:

First line: A JSON array containing student information (example: [["Alice",16,85],["Bob",17,92],["Charlie",16,78]])
Second line: Row index (integer)
Third line: Column index (integer)

Expected output: The element at the specified row and column position

Try it yourself

<?php
// Read the JSON array
$jsonInput = trim(fgets(STDIN));
$students = (array)json_decode($jsonInput, true);

// Read the row index
$rowIndex = intval(fgets(STDIN));

// Read the column index
$colIndex = intval(fgets(STDIN));

// TODO: Write your code below to access the element at the specified row and column


// Output the result
echo $element;
?>

Test yourself

This lesson includes a short quiz. Start the lesson to answer it and track your progress.

Accessing 2D Array Elements

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