The document discusses variables in Python. It defines variables as containers that can store data values. Variables are created when a value is assigned to them and do not require declaration or specification of data type. Strings are represented by characters surrounded by single or double quotes. The document also discusses data types, casting, string declaration, and variable assignment.

1. print("Halt!")
user_input = input("Who goes there? ")
print("You may pass,", user_input)
• input() function was used
• user_input is a variable.
• Variables are like a box that can store some piece of data

2. a = 123.4
b23 = 'Spam'
first_name = "Bill"
b = 432
c = a + b
print("a + b is",c)
print("first_name
is",first_name)
print("Sorted Parts,
After Midnight or",b23)
• The variables in the
above program are
a, b23,
first_name, b,
and c.
The two basic data
types are strings and
numbers.
Variables that are used
to store a value, do not
use quotation marks ("
and ').

3. • Strings are a sequence of letters, numbers and other
characters. In this example, b23 and first_name
are variables that are storing strings.
• Spam, Bill, a+ b is, first_name is,
and Sorted Parts, After Midnight or are
the strings in this program.
The characters are surrounded by " or '.

4. Variables
Variables are containers for storing data
values.
Creating Variables
Python has no command for declaring a
variable.
A variable is created the moment you first
assign a value to it.
Variables do not need to be declared with any
particular type, and can even change type
after they have been set.

5. x = 5
y = "John"
print(x)
print(y)
x = 4 # x is of type int
x = "Sally" # x is now of type str
print(x)

7. In Python,
the data type
is set when
you assign a
value to a
variable:

8. If you want to
specify the data
type, you can
use the
following
constructor
functions:

9. x = 5
y = "John"
print(x)
print(y)
x = 4 # x is of type int
print(type(x))
x = "Sally" # x is now of type str
print(type(x))

10. Casting
If you want to specify the data type of a
variable, this can be done with casting.
x = str(3) # x will be '3'
y = int(3) # y will be 3
z = float(3) # z will be 3.0

11. String variables can be declared either by
using single or double quotes:
Variable names are case-sensitive.

12. Assignment
While executing the statement c = a + b, The right hand side
of the statement (a + b) is evaluated and the result is stored in the
variable on the left hand side (c).
This is called assignment.

13. a = 1
print(a)
a = a + 1
print(a)
a = a * 2
print(a)