Data Types of Array Keys in PHP

Q

What Types of Data Can Be Used as Array Keys in PHP?

✍: FYIcenter.com

A

Two types of data can be used as array keys: string and integer. When a string is used as a key and the string represent an integer, PHP will convert the string into a integer and use it as the key. Here is a PHP script on different types of keys:

<?php 
$mixed = array();
$mixed["Zero"] = "PHP";
$mixed[1] = "Perl";
$mixed["Two"] = "Java";
$mixed["3"] = "C+";
$mixed[""] = "Basic";
print("Array with mixed keys:\n");
print_r($mixed);
print("\$mixed[3] = ".$mixed[3]."\n");
print("\$mixed[\"3\"] = ".$mixed["3"]."\n");
print("\$mixed[\"\"] = ".$mixed[""]."\n");
?>

This script will print:

Array with mixed keys:
Array
(
    [Zero] => PHP
    [1] => Perl
    [Two] => Java
    [3] => C+
    [] => Basic
)
$mixed[3] = C+
$mixed["3"] = C+
$mixed[""] = Basic

Note that an empty string can also be used as a key.

⇒ Index of Array Values in PHP

⇐ Retrieving Values out of an Array in PHP

⇑ Understanding PHP Arrays and Their Basic Operations

⇑⇑ PHP Tutorials

2017-02-03, ∼3533🔥, 0💬

Index of Array Values in PHP
How Values in Arrays Are Indexed in PHP? Values in an array are all indexed their corresponding keys. Because we can use either an integer or a string as a key in an array, we can divide arrays into 3 categories: Numerical Array - All keys are sequential integers. Associative Array - All keys are st... 2017-02-03, ∼4079🔥, 0💬

Data Types of Array Keys in PHP
What Types of Data Can Be Used as Array Keys in PHP? Two types of data can be used as array keys: string and integer. When a string is used as a key and the string represent an integer, PHP will convert the string into a integer and use it as the key. Here is a PHP script on different types of keys:... 2017-02-03, ∼3534🔥, 0💬

Copying an Array in PHP
Can You Copy an Array in PHP? You can create a new array by copying an existing array using the assignment statement. Note that the new array is not a reference to the old array. If you want a reference variable pointing to the old array, you can use the reference operator "&". Here is a PHP... 2017-02-03, ∼3508🔥, 0💬

Testing If a Variable Is an Array in PHP
How To Test If a Variable Is an Array in PHP? Testing if a variable is an array is easy. Just use the is_array() function. Here is a PHP script on how to use is_array(): <?php $var = array(0,0,7); print("Test 1: ". is_array($var)."\n"); $var = array(); print("Test 2: ". is_array($var)."\n"); ... 2016-10-15, ∼2975🔥, 0💬

Understanding PHP Arrays and Their Basic Operations
Where to find tutorials in Understanding PHP Arrays and Their Basic Operations? A collection of tutorials to answer many frequently asked questions on basic understanding of PHP arrays. Clear answers are provided with tutorial exercises on declaring and creating arrays, assigning and retrieving arra... 2016-10-15, ∼2960🔥, 0💬

Order of Array Values in PHP
How the Values Are Ordered in an Array in PHP? PHP says that an array is an ordered map. But how the values are ordered in an array? The answer is simple. Values are stored in the same order as they are inserted like a queue. If you want to reorder them differently, you need to use a sort function. ... 2017-01-29, ∼2888🔥, 0💬

Creating an Array in PHP
How To Create an Array in PHP? You can create an array using the array() constructor. When calling array(), you can also initialize the array with pairs of keys and values. Here is a PHP script on how to use array(): <?php print("Empty array:\n"); $emptyArray = array(); print_r($emptyArray); ... 2016-10-15, ∼2834🔥, 0💬

What Is an Array in PHP
What Is an Array in PHP? An array in PHP is really an ordered map of pairs of keys and values. Comparing with Perl, an array in PHP is not like a normal array in Perl. An array in PHP is like an associate array in Perl. But an array in PHP can work like a normal array in Perl. Comparing with Java, a... 2016-10-15, ∼2761🔥, 0💬

Looping through an Array in PHP
How to Loop through an Array in PHP? The best way to loop through an array is to use the "foreach" statement. There are two forms of "foreach" statements: foreach ($array as $value) {} - This gives you only one temporary variable to hold the current value in the array. foreach ($array as $key=&g... 2017-02-03, ∼2737🔥, 0💬

All rights in the contents of this web site are reserved by the individual author. fyicenter.com does not guarantee the truthfulness, accuracy, or reliability of any contents.