Shashank Kumar
Google Summer of Code 2018 Student with Debian. Google Udacity India Scholar
Python 101
By Shashank
blog.shanky.xyz | realslimshanky
Author - Guido van Rossum
Who Am I
def user ( ):
name = Shashank Kumar
about = shanky.xyz
find me anywhere = @realslimshanky
this slide = slides.com/realslimshanky/python101
What Is ?
A dynamic, interpreted, high-level language
Does not require declaring the types of variables or parameters or methods
Extremely readable
Used for solving a really wide range of problems
Who's using it ?
Why ?
A thriving community of developers and contributors and third party application developers
PyPI (Python Package Index) lists 99381 third-party software projects
Implementation in every field of technology
First Program
The customary "Hello World"
The Main Elements
Identifiers
Keywords
Assignments
Indentation & Comment
Input/Output
The Main Elements
identifier ::= (letter|"_") (letter | digit | "_")*
letter ::= lowercase | uppercase
lowercase ::= "a"..."z"
uppercase ::= "A"..."Z"
digit ::= "0"..."9"
The Main Elements
Keywords
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
The Main Elements
Indentation & Comment
# Single Line Comment
'''
Multiple
Lines
Comment
'''
The Main Elements
Assignments
>>> a = 12
>>> b = 23
>>> a + b
>>> 35
The Main Elements
Input/Output
input()
print()
Handling Data
Variables & Datatypes
Operator & Expression
Condition & Looping
Function
Variables & Datatypes
int
float
string
boolean
int(string)
float(string)
str(integer)
str(float)
type(variable/value)
Operator & Expression
Relational Operators
<
<=
>
>=
==
!=
Logical Operators
and, &
or, |
not
Shorthand Operators
+=
-=
*=
/=
Condition & Looping
if condition:
statement1
if condition: statement2
elif:
statement3
else:
statement4
for x in range(): statement1 statement2
while condition: statement
(continue, break)
Function
def function(parameter):
statement
return
Local and Global Scope
Default Argument
Keyword Argument
Strings
Single Line Declaration
s = 'I am a string'
s ='I am a \
string'
Multiple Line Declaration
s = 'I am a \n string'
s = ''' I
am
a string '''
String Validation
islower() isupper() isalnum() isdigit()
isalpha() istitle()
String Function
String Manipulation
title() lower()
upper() swapcase()
String Strip
strip() lstrip()
rstrip()
String Strip
find() startswith()
endswith()
String Length
len()
Data Structure
Lists
Tuples
Sets
Dictionary
How above are copied?
List
Declaration
L = [1, 2.3, True, 'a', 'bcd']
Getting an element
L[index]
List elements are ordered
List Methods and Some Functions
a.append(2)
a.insert(0,23)
a.count(2)
a.append(list)
a.extend(list)
del list[position]
del list
list[-position]
len[pos1:pos2]
len(list)
enumerate(list)
a.sort()
a.reverse()
a.remove(2)
a.index(3)
zip(list1,list2)
Tuples
Declaration
a = ('hello',1,4,3)
Conversion
list(tuple)
tuple(list)
Tuple elements are odered
Sets
Declaration
a = {'a','b','c'}
b = set('ababcbccbabc')
Set theory
a-b a+b a|b a^b a&b
Set elements are unordered
Dictionary
Declaration
a = {key : value}
Adding New Key,Value
a[key]=value
a.setdefault(key,default)
Getting A Value
a[key]
a.get(key,fallback)
Some helpful Functions
a.keys() a.value() a.items() enumerate()
Dictionary elements are unordered
How above are copied ?
Mutable -> Reference
Immutable -> Value
import copy
copy.copy()
copy.deepcopy()
What are Mutable and Immutable objects ?
File Handling
Opening A File f=open('filename')
Option Arguments
mode
encoding
Closing A File f.close()
Alternative with open('filename') as fobj:
File Handling
Reading From A File f=open('filename')
f.tell()
f.read()
f.seek()
Writing To A File f=open('filename', 'a')
f.write('Hello')
Error Handling
try:
print(2/0)
except:
print('Error Encountered')
finally:
print('No matter what happens, I will run')
Classes
Defining A Class
class cname():
a=10
def amethod(self):
print(self.a)
Classes
Creating An Instance Of Class
myinstance = cname()
Creating A Class Constructor
def __init__(self, b):
self.a=b
Classes
Getting and Setting the properties
myinstance = cname()
print(myinstance.a)
myinstance.a = 12
Classes
Inheritance
class a():
age=20
class b(a):
def show(self):
print(self.age)
Method
myinstance = b()
myinstance.show()
Thank You
For any query
abc@shanky.xyz | @realslimshanky
Python 101
By Shashank Kumar
