Values in Python can belong to different data types including numbers, strings, and lists. Numbers include integers, floating point numbers, and complex numbers. Strings are a sequence of characters that can be defined using single quotes, double quotes, or triple quotes. Common data types in Python include numbers, strings, lists, tuples, and dictionaries. Lists are mutable sequences while tuples are immutable sequences.

1. Values and Data types in Python

2. Value
• A value is one of the fundamental things, like
a number, a character or a string that program
manipulates.
Example
2,42.0,’Hello,World’ The value belong to
different types.

3. Literal Constants
 The value of a literal constant can be used directly in programs. For example,
7, 3.9, 'A', and "Hello" are literal constants.
 Numbers refers to a numeric value. You can use four types of numbers in
Python program- integers, long integers, floating point and complex numbers.
 Numbers like 5 or other whole numbers are referred to as integers. Bigger
whole numbers are called long integers. For example, 535633629843L is a
long integer.
 Numbers like are 3.23 and 91.5E-2 are termed as floating point numbers.
 Numbers of a + bi form (like -3 + 7i) are complex numbers.
9/5/2022 Introduction to python 3

4. Example
9/5/2022 Introduction to python 4
Strings
A string is a group of characters.
• Using Single Quotes ('): For example, a string can be written as 'HELLO'.
• Using Double Quotes ("): Strings in doubles are exactly same as those in
single quotes. Therefore, 'HELLO' is same quoteas "HELLO".
• Using Triple Quotes (''' '''): You can specify multi-line strings using triple
quotes. You can use as many single quotes and double quotes as you
want in a string within triple quotes.
Examples:

5. • Data type refers to the type and size of data.
Variables can hold values of different data types.
Python is a purely object oriented language. It
refers to everything as an object, including
numbers and strings.
• The standard data types supported by python
includes:
– Number
– Boolean
– String
– List
– Tuple
– Dictionary

6. Numbers
• Numbers refers to a numeric value. It includes integers, long
integers, floating point, and complex numbers.
• Integers are whole numbers with no fractional parts. They can be
either positive, negative or zero value. Python displays long
integers with an uppercase L (56788333354533L is a long integer).
• Floating point numbers are numbers with fractions or decimal
points. Floating point values can be expressed in scientific notation
using the letter ‘e’ or ‘E’.
• A complex number is a number that can be expressed in the form a
+ bi, where a and b are real numbers, and i is the imaginary unit.

7. • The type() function can be used to know which data type
a variable or a value belongs to.
• The isinstance() function to check if an object belongs to
a particular class.
Example:
a = 5
print(a, "is of type", type(a))
a = 2.0
print(a, "is of type", type(a))
a = 1+2j
print(a, "is complex number?", isinstance(1+2j,complex))
Output:
5 is of type <class 'int'>
2.0 is of type <class 'float'>
(1+2j) is complex number? True

8. • Boolean is another data type in Python.
• A variable of Boolean type can have one of the
two values- True or False.
List
• List is an ordered sequence of items. It is one of
the most used data type in Python and is very
flexible. All the items in a list do not need to be of
the same type.
• Lists are mutable. The elements in the list can be
modified.
• To declare a list in python, separate the items
using commas and enclose them within square
brackets [ ].

9. >>> a = [1, 2.2, 'python'] The slicing operator [ ] is
used to extract an item or a range of items from a
list. Index starts form 0 in Python.
Example:
>>>a = [5,10,15,20,25,30,35,40]
>>>a[2]
15
>>>print("a[0:3] = ", a[0:3])
[5,10,15]

10. • Tuple
• Tuple is an ordered sequence of items same as
list. The only difference is that tuples are
immutable. Tuples once created cannot be
modified.
• It is defined within parentheses ( ) where items
are separated by commas.

11. Example:
>>> t = (5,'program', 1+3j)
print("t[1] = ", t[1])
print("t[0:3] = ", t[0:3])
Output:
t[1] = program
t[0:3] = (5, 'program', (1+3j))

12. Strings
• A String in python can be a series or a
sequence of alphabets, numerals and special
characters.
• Single quotes or double quotes are used to
represent strings.
• >>> s = "This is a string"
• Strings are immutable.

13. Example:
s = 'Hello world!'
print("s[4] = ", s[4]) # s[4] = 'o'
print("s[6:11] = ", s[6:11]) # s[6:11] = 'world'
Output:
s[4] = o
s[6:11] = world