What is variables?
Variables are used to store information to be referenced and manipulated in a computer program. Their sole purpose is to label and store data in memory, those are then available publicly or privately.
In PHP to declare a variable $ sign, follows the name of the variable.
<?php $text = "Hello World!"; $a = 40; $b = 23.5; echo $text; echo $a; echo $b; ?>
When above program is executed, the variable $text will hold the value Hello World and variables $a and $b will hold 100 & 23.5 respectively.
When assigning a text value to variable, put quotes around the value. Unlikely other programming language, PHP has no command to declare a variable.
A variable can have a short name (like x and y) or a more descriptive name (age, first_name, salary, gender).
PHP variables definition rules:
- A variable starts with the
$sign, followed by the name of the variable
- A variable must start with a letter or the underscore character
- A variable can’t start with a number
- A variable can only contain alpha-numeric characters and underscores (A-z, 0-9, and _ )
- variables are case-sensitive like: (
$NAMEare two different variables)
Likewise PHP, Python also has no command for declaring a variable. A variable is created at the moment they are assigned a value.
age = 30 country = "Pakistan" print(age) print(country)
Variables do not need to be declared with any particular type, and can even change type after they have been set.
y = 100 # y is of type int y = "Pakistan" # y is now of type str # Type casting x = str(3) # x will be '3' y = int(3) # y will be 3 z = float(3) # z will be 3.0
Unlikely PHP, in Python string variables can be declared either by using single or double quotes.
country = "Denmark" # is the same as country = 'Denmark'
In Python likewise PHP a variable can have a short name (like x and y) or a more descriptive name (age, first_name, salary, gender).
Rules for Python variables:
- A variable name must start with a letter or the underscore character
- A variable name cannot start with a number
- A variable name can only contain alpha-numeric characters and underscores (A-z, 0-9, and _ )
- Variable names are case-sensitive (name, Name and NAME are three different variables)