Python basics

Jyoti Shukla, SME
Copyright 2020 @SquadInfotech,
All rights reserved.

 General purpose high level programming/
scripting language
 Invented by Guido Van Rossam
 Combination of:
◦ Functional programming Language from C
◦ OOPS concept from C++.
◦ Scripting language from perl and shell script
◦ Modular programming language from Modula-3.

 Open Source
 Platform Independent
 Portable
 Simple and easy to learn
 Dynamically Typed
 Interpreted Language
 Extensible
 Broad Standard Library
 Supports both function oriented concept and
object oriented concept

 Desktop application
 Web applications
 Database Application
 Networking applications
 Games
 Data analysis
 Machine Language
 Artificial Intelligence

 Google
 YouTube
 Dropbox
 NASA
 and many more

Link: https://www.python.org/downloads/

 Python 3.8.2 introduced in 24 Feb 2020
 ..
 Python 3.8 introduced in 14 Oct 2019
 ....
 Python 3.0 introduced in Dec 2008
 Python 2.0 introduced in October 2000
 Python 1.0 introduced in Jan 1994
Python is not backward compatible.

 There are 33 reserve keywords in python.
'False', 'None', 'True', 'and', 'as', 'assert', 'break',
'class', 'continue', 'def', 'del', 'elif', 'else',
'except', 'finally', 'for', 'from', 'global', 'if',
'import', 'in', 'is', 'lambda', 'nonlocal', 'not',
'or', 'pass', 'raise', 'return', 'try', 'while', 'with',
'yield'

 Only A-Z, a-z and 0-9 can be used to create
an identifier but shouldn't start with a digit.
 Identifiers are Case Sensitive.
 Reserve Keywords are not allowed as
Identifiers.
 No long limit.
 Only underscore ‘_’, a special character is
allowed in an identifier.
 Eg: counter, counter1, arr_count etc

 Int
 Float
 Complex
 Bool
 Str
 Bytes
 Bytearray
 Range
 List
 Tuple
 Set
 Frozenset
 Dict
 None

 Function for type casting
 int()
 float()
 complex()
 bool()
 str()

• Arithmetic operators
• Assignment operators
• Comparison operators
• Logical operators
• Identity operators
• Membership operators
• Bitwise operators

 + Addition (x + y)
 - Subtraction (x – y)
 * Multiplication (x * y)
 / Division (x / y)
 % Modulus (x % y)
 ** Exponentiation (x ** y)
 // Floor division (x // y)

 = x = 5 (x = 5)
 += x+=5 (x = x + 5)
 -= x -= 5 (x = x – 5)
 *= x *= 5 (x = x * 5)
 /= x /= 5 (x = x / 5)
 %= x %= 5 (x = x % 5)
 //= x //= 5 (x = x // 5)
 **= x **= 5 (x = x ** 5)
 &= (x &= 5) (x = x & 5)
 |= x |= 5 (x = x | 5)
^= x ^= 5 (x = x ^ 5)

 > (Greater than)
 < (Lesser than)
 == (Equal to )
 != (Not equal to)
 >= (Greater than or equal to)
 <= (Less than or equal to)

and := if both values are true then only result
is true
Or:=True if either of the operands is true
Not:= complement

 & Bitwise AND
 |Bitwise OR
 ~Bitwise NO
 ^Bitwise XOR
 >>Bitwise right shift
 <<Bitwise left shift

 are used to test whether a value or variable is
found in a sequence
(string, list, tuple, set and dictionary).
 In:=True if value/variable is found in the
sequence
 Not in:=True if value/variable is not found in
the sequence

 They are used to check if two values (or
variables) are located on the same part of the
memory. Two variables that are equal does
not imply that they are identical.
 is :=True if the operands are identical (refer
to the same object)
 is not := True if the operands are not
identical (do not refer to the same object)

Syntax Example (Odd Even)
Syntax:
if condition:
#code
else:
#code
num= int(input("Enter
the number to check:
"))
if num%2 is 0:
print("even number")
else:
print("odd number")

Syntax Example
if condition:
#code
if condition:
#code
else:
#code
else:
#code
per=int(input("Enter your
percentage: "))
if per >= 60:
exp= int(input("Enter the
number of experience: "))
if exp >= 2:
print("eligible for job")
else:
print("not eligible for job")
else:
print("not qualified“)

Syntax Example
if condition:
#code
elif condition:
#code
elif condition:
#code
else:
#code
per= int(input("Enter your
percentage: “))
if per >= 90:
print("A grade")
elif per >=70 and per<90:
print("B grade")
elif per >=50 and per<70:
print(“C grade")
else:
print(“Be positive, Work
hard")

Syntax Example
while (condition):
#code
num=int(input(“Enter a
number: "))
counter=1
print(“Below are even
numbers: ”)
while counter<=num:
if counter%2==0:
print(counter)
counter+=1

Syntax Example
for counter in range
(lower limit,
upper limit,
[increment factor]):
#code
for i in range(1,5):
# default increment is1
print(i)
for i in range(5,0,-1):
#decrementing by -1
print(i, end=“ ”)

 Strings are arrays of bytes representing
Unicode characters.
 Python does not have a character data type.
 A single character is simply a string with a
length of 1.
 Square brackets can be used to access
elements of the string.
 Strings can be created using single, double or
even triple quotes.

 String in single quotes cannot hold any other
single quoted character in it because the
compiler won’t recognize where to start and
end the string.
 To overcome this error, double quotes is
preferred, because it helps in creation of
Strings with single quotes in them.
 For strings which contain Double quoted
words in them, use of triple quotes is
suggested. Along with this, triple quotes also
allow the creation of multiline strings.

Single Quote
Double Quoted string has
a Single Quote
# Creation of String
# with single Quotes
str1 = 'Welcome to the
Coder Technologies‘
print(str1)
# Creating a String
# with double Quotes
str2 = "I'm learning
python“
print(str2)

Triple Quotes
Multiline with Triple
quotes
# Creating a String
# with triple Quotes
str3 = ‘’’I'm learning
python and I’m lovin’
it’’’
print(str3)
# Creating multiline
# strings
str4 = '''hi
how are you?
This lockdown is so
boring! '''
print(str4)

 Access characters within a string
 Concatenating
 Iterating
 Formatting
 Built-in string methods

There are four collection data types:
 List: Ordered and changeable. Allows
duplicate members.
 Tuple: Ordered and unchangeable. Allows
duplicate members.
 Set: Unordered and un-indexed. No duplicate
members.
 Dictionary: Unordered, changeable and
indexed. No duplicate members.

Python basics

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