How do you determine the data type of a variable in PHP?
PHP is more tolerant than other programming languages and does not require a fixed data type to be specified for a variable. In fact, there is not even an opportunity to do so. Nevertheless, the value of each variable has a data type that influences the processing of this value. For example, adding integers behaves differently than adding strings.
gettype()
To find out what data type the value of a variable has, gettype($var) can be used. This function returns one of the following string, which correspond to the known data types in PHP: ‘boolean’, ‘integer’, ‘double’, ‘string’, ‘array’, ‘object’, ‘resource’, ‘NULL’, ‘unknown type’. Floats are represented by ‘double’.
<?php
function func($par) {
echo("Data type of '".$par."' is '".gettype($par)."'.\n");
}
func(50);
func(2.5);
func("hello");
func(null);
?>
Output:
Data type of '50' is 'integer'. Data type of '2.5' is 'double'. Data type of 'hello' is 'string'. Data type of '' is 'NULL'.
[st_adsense]
is_* functions
The function gettype() should only be used to output the datatype of a variable. Testing for special datatypes – with this function – is not recommended, because the returns may change at some point. Instead, the functions is_boolean($var), is_string($var), is_float($var), is_array($var), is_object($var), is_resource($var) and is_null($var) should be used.
<?php
function square($val)
{
// Only integers or floats should be squared by this function
// an error is thrown for all other data types.
if (!is_int($val) && !is_float($val))
{
throw new Exception('Invalid parameter passed. '
.'Integer was expected, '.gettype($val).' was given.');
}
return ($val * $val);
}
// square with 2 as a number
var_dump(square(2));
// square with 2 as a string, produces an error
try
{
var_dump(square("2"));
}
catch (Exception $e)
{
echo($e->getMessage());
}
?>
Output:
int(4) Invalid parameter passed. Integer was expected, string was given.
[st_adsense]
- Factorial Program in PHP Using Recursive Function
- Factorial in PHP Using For Loop
- How to Generate Random String in PHP
- Warning: Cannot modify header information – headers already sent
- How to send mail from localhost in PHP using WAMP server
- How to send mail from localhost in PHP using XAMPP
- How to Send an Email in PHP
- How to Validate an Email Address in PHP
- How to Check Format of Date in PHP
- How to check if a URL is valid in PHP
- How to Check Website Availability with PHP
- How to Generate Random Numbers in PHP
- How to Calculate Age from Date of Birth in PHP
- How to Extract Content Between HTML Tags in PHP
- How to check if file exists on remote server PHP
- How to get the client IP address in PHP
- How to Get IP Address of Server in PHP
- How to declare a global variable in PHP
- How to refresh a page with PHP
- How to get first day of week in PHP
- How to Change Max Size of File Upload in PHP
- How to compare two dates in PHP
- How to open a PDF file in browser with PHP
- How to Download file from URL using PHP
- How to remove an array element based on key in PHP
- How to get random value from an array in PHP
- How to calculate sum of an array in PHP
- How to remove null or empty values from an array in PHP
- How to Populate Dropdown List using Array in PHP
- How to get all the keys of an associative array in PHP
- How to get a value from an array in PHP
- How to remove a specific element from an array in PHP
- How to sort an associative array by value in PHP
- How to sort an associative array by key in PHP
- How to Check If a String Contains a Specific Word in PHP
- How to get the current date and time in PHP
- How to redirect to another page in PHP
- How to remove all spaces from a string in PHP
- Convert a date DD-MM-YYYY to YYYY-MM-DD in PHP
- Convert a date YYYY-MM-DD to DD-MM-YYYY in PHP
- How to get the current year in PHP
- How to convert a string to an integer in PHP
- How to get the first element of an array in PHP
- How to convert date to timestamp in PHP
- PHP: Compare two arrays and get the difference
- How to remove duplicates from an array in PHP
- How to sort an array in alphabetical order in PHP
- How to merge multiple arrays into one array in PHP
- How to add an element to the end of an array in PHP
- How to add an element to the beginning of an array in PHP
- How to remove the last element from an array in PHP
- How to remove the first element from an array in PHP
- How to replace part of a string in PHP
- How to count repeated words in a string in PHP
- PHP – Count Array Elements
- How to Reverse an Array in PHP
- How to check if a value exists in an array in PHP
- How to check if a key exists in an array in PHP
- How to reverse a string in PHP
- How to check if a variable is null in PHP
- How to check if a variable is empty in PHP
- How to check if a variable is undefined in PHP
- Convert HTML entities back to characters – PHP
- How to find the length of a string in PHP
- How to capitalize the first letter of a string in PHP
- PHP – Uppercase the first letter of each word in a string
- How to convert a string to lowercase in PHP
- How to compare two strings in PHP
- How to get the URL of the current page in PHP
- How to convert a string into an array in PHP
- How to extract a substring from a string in PHP
- How to count number of words in a string in PHP
- How to remove special characters from a string in PHP
- How to replace a word in a string in PHP
- How to Concatenate Two Strings in PHP
- How to count the number of characters in a string in PHP
- PHP – Remove spaces at the beginning and end of a string
- How to filter an array by value in PHP
- PHP – Get Domain Name from URL
- How to create a log file in PHP
- How to add days to a date in PHP
- PHP – Get file extension
- How to save an image from a URL in PHP
- How to Edit PHP ini File in Ubuntu Terminal
- How to increase the execution time of a PHP script
- How to enable cURL in PHP WAMP, XAMPP, and Ubuntu
- Convert Array to JSON in PHP
- PHP – Read JSON file
- How to display HTML tags as plain text using PHP
- PHP – Create JSON file
- How to convert result of MySQL query in JSON format
- PHP – Read CSV File into an Array
- How to convert an object to associative array in PHP
- How to extract or unzip a folder on FTP server in PHP
- How to Import CSV File in MySQL PHP
- Get Data From a Database Without Refreshing the Browser Using Ajax
- How to connect to Oracle database with PHP
- Connect to a PostgreSQL database with PHP PDO
- PHP – Convert Multidimensional Array to XML file
- What is PHP and how can I learn it?
- Hello World in PHP
- Comments in PHP
- How to Define a Variable in PHP
- PHP global variable with Example
- PHP Variable Scope
- PHP – Static Variables
- Type casting in PHP
- PHP Type Juggling
- Variable variables in PHP
- How to echo an array in PHP?
- How to Convert Decimal to Binary in PHP?
- How to Convert Binary to Decimal in PHP?
- How to assign multiple variables at once in PHP
- How to extract $_GET / $_POST parameters in PHP
- How to use $_GET in PHP?
- How to get a variable name as a string in PHP?
- How to print all defined variables and values in PHP
- PHP References: When to Use Them, and How They Work
- List of Superglobal Variables in PHP
- How to return a variable by name from a function in PHP
- How to delete a variable in PHP
- What is the difference between == and === in PHP
- How to check if a variable is NULL in PHP?
- How to check if an object is an instance of a specific class in PHP?
- How to check if a variable is a Boolean in PHP?
- How to check if a variable is a String in PHP?
- How to check if a variable is an Integer in PHP?
- How to check if a variable is a float in PHP?
- How to check if a variable is an array in PHP?
- How to check if a variable is undefined in PHP?
- How do you determine the data type of a variable in PHP?
- Difference between Include and Require in PHP
- How to combine HTML and PHP?
- How to add a new line within echo in PHP?
- How to display PHP variable values with echo, print_r, and var_dump
- The 6 best PHP frameworks in 2021
- PHP MCQ – Multiple Choice Questions and Answers – Basics – Part 1
- PHP MCQ – Multiple Choice Questions and Answers – Basics – Part 2
- PHP MCQ – Multiple Choice Questions and Answers – Basics – Part 3
- PHP Questions and Answers – Functions – Part 1
- PHP Questions and Answers – Functions – Part 2
- PHP Questions and Answers – Arrays – Part 1
- PHP Questions and Answers – Arrays – Part 2
- PHP Questions and Answers – Arrays – Part 3
- PHP Questions and Answers – Arrays – Part 4
- PHP Questions and Answers – Object-Oriented OOP – Part 1
- PHP Questions and Answers – Object-Oriented OOP – Part 2
- PHP Questions and Answers – Object-Oriented OOP – Part 3
- PHP Questions and Answers – String – Part 1
- PHP Questions and Answers – String – Part 2
- PHP Questions and Answers – Regular Expressions
- PHP Questions and Answers – Exception Handling
