Python Data-Types

Akhil Kaushik
Asstt. Prof., CE Deptt.,
TIT Bhiwani
Data Types in Python

Python Introduction
• Python is a dynamic-typed language (uses interpreter).
• Many other languages are static typed, such as C/C++
and Java (use compiler).
• A static typed language requires the programmer to
explicitly tell the computer what type of “thing” each
data value is.

Python Introduction
• In Python, you simply give your variables names
and assign values to them.
• The interpreter takes care of keeping track of what
kinds of objects your program is using.
• This also means that you can change the size of
the values as you develop the program.

Names and Tokens
• Identifiers can be of unlimited length.
• Names and identifiers are case sensitive.
• Allowed characters: a-z, A-Z, 0-9 & underscore.
• It must begin with a letter or underscore.
• Names/variables in Python do not have a type.
Values have types.

Names and Tokens
• Naming conventions Not rigid, but:
–Modules and packages - all lower case.
–Global and constants – Upper case.
–Classes - caps with initial upper.
–Methods and functions – All lower case with words
separated by underscores.
–Local variables - Lowercase (with underscore
between words) or bumpy caps with initial lower or
your choice.

Blocks and Indentation
• Python represents block structure
and nested block structure with
indentation, not with begin and
end brackets.
• Indentation is 4 spaces and no
hard tabs.
• Reduces clutter. Eliminates all the
curly brackets.

Modules & Packages
• Modules correspond to files with a "*.py"
extension.
• Packages correspond to a directory (or folder) in
the file system; a package contains a file named
"__init__.py". Both modules and packages can be
imported.
• Packages - A directory containing a file named
"__init__.py".

Operators
• Python defines the following operators:
• The comparison operators <> and != are alternate
spellings of the same operator.
• Logical Operators: and, or, not, is, in

Operators’ Precedence
• Table summarizes the
operator precedence in
Python, from lowest
precedence to highest
precedence.
• Operators on the same line
have the same precedence.
• At end, +,-,*, / come.

Data Types
• Numeric Types
• Strings
• Lists
• Tuples
• Dictionaries
• Sets
• Files, Boolean, etc.

Data Types - Numeric
• Python supports 2 types of numbers:
– Integer
Ex: myint = 7
print(myint)
– Float
Ex: myfnt = 7.0
print(myfnt)
myff = float(28)
print(myff)
– complex nos: 3.14j

Data Types - Strings
• Strings in Python are identified as a contiguous set
of characters represented in the quotation marks.
• Python allows either pair of single or double quotes.
• Advantage of using double quotes is that we don’t
need to worry about apostrophes.
• More than 1 variable can be assigned values
simultaneously.

Ex: mys = ‘Hello’
print(mys)
myss = “Mate”
print(myss)
print(mys + “ ”+myss)

• Subsets of strings can be taken using the slice
operator ([ ] and [:] ) with indexes starting at 0 in the
beginning of the string and working their way from -
1 to the end.
• The plus (+) sign is the string concatenation
operator and the asterisk (*) is the repetition
operator.

Data Types – Formatted Strings
f-strings are string
literals that have an ‘f’
at the beginning and
curly braces containing
expressions that will be
replaced with their
values.

Data Types - Lists
• It is like a structure that
may contain different types
of data elements.
• Ex: list1 = [2233, 88.76,
45+6j, “wfh”, 56]
• Ex: list1[2] = “new”

Data Types - Lists
The concept of
slicing can also
be applied here:

Data Types - Tuples
• It is similar to lists, but
once created it cannot
be edited.
• Tuple uses parenthesis
() instead of square
brackets[].

Data Types - Dictionary
• It is an alternate to the switch-case construct and is
used as a key-value pair.
• Each key is separated from its value by a colon (:),
the items are separated by commas, and the whole
thing is enclosed in curly braces.
• An empty dictionary without any items is written
with just two curly braces, like this: {}.

Data Types – Boolean
• Boolean type provides two built-in values:
– True and False.
• It denotes by the class bool.
• True can be represented by any non-zero value or
'T' whereas false can be represented by the 0 or 'F'.
• Ex: print(type(True))
• Ex: print(type(False))

Data Types - Sets
• Python Set is the unordered collection of the data
type.
• It is iteratable, mutable(can modify after creation),
and has unique elements.
• In set, the order of the elements is undefined.
• The set is created by using a built-in
function set(), or a sequence of elements is passed
in the curly braces and separated by the comma.

Data Types - Sets
Ex: a = {5,2,3,1,4}
# printing set variable
print("a = ", a)
# data type of variable a
print(type(a))

Data Types - Sets
Ex: set1 = set()
set2 = {'James', 2, 3,'Pyt'}
print(set2)
set2.add(10)
print(set2)
set2.remove(2)
print(set2)

Akhil Kaushik
akhilkaushik05@gmail.com
9416910303
CONTACT ME AT:
Akhil Kaushik
akhilkaushik05@gmail.com
9416910303
THANK YOU !!!

Python Data-Types

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