Basics and Fundamentals of
Python
Python is more powerful
language in modern days. Python is widely used in AI and machine learning.
Now open pycharm and
create a app.py file start with first code-
print("MK Study Journal") # will print MK Study Journal in console
Beauty of python is we
need no to create any explicit data variable, it automatically create the
variable as assigned value. Refer below
print("MK Study Journal") # will print MK Study Journal in console
variable1 = "MK Study Journal"
print(variable1) # will print 'MK Study Journal'
in console
variable2 = True
print(variable2) # will print 'True' in console
variable3 = 123
print(variable3) # will print '123' in console
Take user input-
variable = input("Please enter True\False:
")
print(variable) # will print user input
True\False
Conditional statement-
variable = input("Please enter number
between 1 to 10: ")
if variable < 5:
print("Won")
elif variable < 10:
print("loss")
else:
print("Invalid input")
Multiple assignment-
a = b = c = 1
a,b,c = 1,2,"MK Study Journal"
print(a) # will print 1
print(b) # will print 2
print(c) # will print MK Study Journal
Python String:-
variable = "MK Study Journal"
print(variable[0]) # will print
character at index 0 = M
print(variable[0:5]) # will print character form
index 0 to 5 = MK St
print(variable[-1]) # will print
last character = l
print(variable[:]) # will print compete string = MK
Study Journal
Data Type conversion:-
variable = input("Please enter you birth
year ") #variable is treated as String
age = 2019 - int(variable) # string to int conversion
print(age) # will print age if user input
1988 the age will be 31
Types of operator-
var1 = 10
var2 = 2
print(var1+var2) # addition 12
print(var1-var2) # substraction 8
print(var1*var2) # * Multiplication 20
print(var1/var2) # / Division 50
print(var1%var2) # % Modulus 0
print(var1**var2) # ** Exponent 100
print(var1//var2) # // floor division 5
Loop Control:-
# while loop
count = 0
while (count < 10):
print('The count is:', count)
count = count + 1
# for loop
for char in 'MKStudyJournal':
print('Current Letter :', char)
# nested loop
var1 = 2
while(var1 < 100):
var2 = 2
while(var2 <=
(var1 / var2)):
if not(var1 %
var2): break
var2 = var2 + 1
if (var2 >
var1/var2) : print (var1, " is prime number")
var1 = var1 + 1
Triple quotes-print multiline string-
# triple quote to print multi
line string
variable = """ Hello Friends
Welcome in MK Study Journal"""
print(variable)
List operations-
list1 = ['M','T', 'W','T', 'F','S','S']
list2 = [1, 2, 3, 4, 5, 6, 7 ];
print ("list1[0]: ", list1[0]) # list1[0]: M
print ("list2[1:5]: ", list2[1:5]) # list2[1:5]: [2, 3, 4, 5]
# updating value in list
list1[0] = 'Mon'
list2[1] = 'two'
print ("list1[0]: ", list1[0]) # list1[0]: Mon
print ("list2[1]: ", list2[1]) # list2[1]: two
print (len(list1[1])) # length of list1 is 7
print (len(list2[1])) # length of list2 is 7
# deleting value in list
del list1[0]
del list2[1]
print ("list1[0]: ", list1[0]) # list1[0]: T
print ("list2[1]: ", list2[1]) # list2[1]: 3
# length of list after one element deletion
print (len(list1[1])) # length of list1 is 6
print (len(list2[1])) # length of list2 is 6
print (max(list1[1])) # max element in list1 is T
print (min(list2[1])) # min element in list1 is 1
Tuples – tuples is a sequence of immutable python
objects.
tuple1 = (1, 2, 3, 4, 5 );
tuple2 = "a", "b", "c", "d";
emptyTuple = ()
singleValueTuple = (1,)
print(tuple1) # print (1, 2, 3, 4, 5)
print(tuple2) # print ('a', 'b', 'c', 'd')
print(emptyTuple) # print ()
print(singleValueTuple) # print (1,)
print(tuple1[0]) # print 1
print(tuple1[-1]) # print 5
print(tuple1[1:4]) # print (2, 3, 4)
tuple3 = tuple1+tuple2 # updating tuple
print(tuple3) # print (1, 2, 3, 4, 5, 'a', 'b', 'c', 'd')
del tuple3 # delete entire tuple
print(tuple3) # NameError: name 'tuple3' is not defined
tuple3 = ('Hi!',) * 4
print(tuple3) # print ('Hi!', 'Hi!', 'Hi!', 'Hi!')
print('Hi!' in tuple3) # print true
Dictionary: - Dictionary
is a key value pair separated by: and represent in curly braces.
Like –{key1:value1,
key2:value2}
dictionary1 = {} # empty dictionary
dict = {'key1': 'value1', 'key2': 'value2', 'key3': 'value3'}
print ("dict['key1'] value: ", dict['key1']) # dict['key1'] value: value1
print ("dict['key2'] value: ", dict['key2']) # dict['key2'] value: value2
dict['key1'] = 1;
# update
existing entry
print ("dict['key1'] value: ", dict['key1']) # dict['key1'] value: 1
del dict['key1']; # remove entry with key 'key1'
print ("dict['key1'] value: ", dict['key1']) # KeyError: 'key1'
dict.clear(); # remove all entries in dict
print (dict) # {}
del dict ; # delete entire dictionary
Function block:-
Function blocks begin with
the keyword def followed by the function name and parentheses ( ( ) ).
A return statement with no
arguments is the same as return None.
def checkPrime( num):
if num%2 != 0:
print("Prime number")
else:
print("Not a Prime number")
def factorial(num):
fatorial = 1;
while num >= 1:
fatorial = fatorial*num
num = num-1
print("factorial value is ",fatorial)
number = int(input("Enter number : ")) # user input number
factorial(number)
checkPrime(number)
Handling with files
import os
fileObject = open("mkstudyjournal.txt", "w+") # open file in wb-Opens a file in writing and reading
print("Name of the file: ", fileObject.name) # Name of the file:
mkstudyjournal.txt
fileObject.write( "second-MK Study
Journal") # write into file
fileObject.write( "third-MK Study Journal") # write into file
print(fileObject.seek(0,0)) # reset reader pointer position
0
print("", fileObject.read(45)) # read file
print(fileObject.tell()) # Current file position 45
fileObject.close()
os.rename("mkstudyjournal.txt", "ren-mkstudyjournal.txt")
os.makedirs("/temp/text") # make directory
os.removedirs("/temp/text") # remove directory
Exception Handling-
try:
fileObject = open("test1", "w")
fileObject.write("Exception
handling!!")
except IOError:
print("Error: can\'t find file or read data")
else:
print("success")
fileObject.close()
try:
var1 = int(input("Enter number: "))
var = 10/var1
except ValueError: # if input value is not numeric
print("Error: can not convert to
int, Invalid number")
except ZeroDivisionError: # if input value is 0
print("Error: can\'t divide by zero")
else:
print("success")
User defined error-
class CustomkError(RuntimeError):
def __init__(self, arg):
self.args = arg
try:
raise CustomkError("user defined error")
except CustomkError:
print("Error: custom error")
Object oriented
class Student:
fullName = "test"
def __init__(self, firstName, lastName):
self.firstName = firstName
self.lastName = lastName
Student.fullName = firstName+" "+lastName
def fullName(self):
print("Student name: ", Student.fullName)
def displayStudent(self):
print("FirstName : ", self.firstName, ", LastName: ", self.lastName)
student = Student("Manoj", "Kumar")
student.displayStudent()
# inheritance property implementation
class Person:
fullName = "test"
def __init__(self, firstName, lastName):
self.firstName = firstName
self.lastName = lastName
Student.fullName = firstName + " " + lastName
def displayPerson(self):
print("Hello parent", Student.fullName)
def displayWelcome(self):
print("Welcome")
class Student(Person):
def __init__(self, firstName, lastName):
self.firstName = firstName
self.lastName = lastName
Student.fullName = firstName+" "+lastName
def displayPerson(self):
print("Hello child", Student.fullName)
student = Student("ChildFN", "ChildLN")
student.displayWelcome() # call parent method print Welcome
# method overriding
student.displayPerson() # call child method print Hello child ChildFN ChildLN
person = Person("ParentFN", "ParentLN")
person.displayPerson() # parent method print -Hello parent ParentFN ParentLN
CGI Programming in Python-
Create httpd.cfg with
below content –
<Directory "/cgi-bin">
AllowOverride None
Options ExecCGI
Order allow,deny
Allow from all
</Directory>
<Directory "/cgi-bin">
Options All
</Directory>
Create python file in
directory /cgi-bin CGI.py
import cgitb
cgitb.enable()
print("Content-Type: text/html\n")
print("<!doctype html>")
print("<h2>Welcome in MK Study Journal</h2>")
print("<h2>Thank you !!</h2>")
Run below command in
terminal-
python -m
http.server --bind localhost --cgi 8080
Open browser-
terminal command will be as follows-
Navigation between CGI-
Create below
textareasubmit.py file-
import cgitb
cgitb.enable()
print("Content-Type: text/html\n")
print("<!doctype html>")
print("<body>")
print('<form action = "/cgi-bin/textarea.py" method = "post"')
print('<textarea name = "textArea" cols = "40" rows = "4">')
print("</textarea>")
print('<input type = "submit" value = "Submit" />')
print("</form>")
print("</body>")
Create below
textareareader.py file
import cgi, cgitb
form = cgi.FieldStorage()
if form.getvalue('textArea'):
text_area = form.getvalue('textArea')
else:
text_area = "Not entered"
print("Content-type:text/html\r\n\r\n")
print("<html>")
print("<body>")
print("<h2> Entered Text is %s</h2>" % text_area)
print("</body>")
Now open below url –
Multithreading in Python-
import threading
import time
class PrintNumbers(threading.Thread):
def __init__(self):
threading.Thread.__init__(self)
def run(self):
for i in range(10):
time.sleep(1) #sleep for 1 seconds
print(i) # will print 0 to 9
print(threading.current_thread()) # threadName <PrintNumbers(Thread-1, started 19464)>
thread1 = threading.Event()
t1 = PrintNumbers()
t1.start()
import threading
class PrintNumbers(threading.Thread):
def __init__(self, startIndex, lastIndex, step, set_event, clear_event):
threading.Thread.__init__(self)
self.startIndex = startIndex
self.lastIndex = lastIndex
self.step = step
self.set_event = set_event
self.clear_event = clear_event
def run(self):
for i in range(self.startIndex, self.lastIndex, self.step):
print(i)
self.set_event.set()
self.clear_event.clear()
self.clear_event.wait()
self.set_event.set()
thread1 = threading.Event()
thread2 = threading.Event()
t1 = PrintNumbers(0, 10, 2, thread1, thread2)
t2 = PrintNumbers(1, 10, 2, thread2, thread1)
t1.start()
t2.start()
t1.join()
t2.join()
