PHP vs Python #2: Variables

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.

PHP Variables

In PHP to declare a variable $ sign, follows the name of the variable.

PHP Example:

<?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: ($name and $NAME are two different variables)

Python Variables

Likewise PHP, Python also has no command for declaring a variable. A variable is created at the moment they are assigned a value.

Python Example:

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)
Author: Danyal
I'm working as programmer since 2002. Born, grew up, studied and worked in Pakistan now Im located in Denmark since 2006.