Python Coding

Echo server client
Echo server client with multi-threading support
Echo client with command line input (todo)
Fibonacci series with command line input
Word count of a text file
Format example in print
FTP program to transfer file (todo)
monitor script on ifconfig tool (todo)
Program to ask random questions from a question bank (todo)
Script on calculator (bc tool) (todo)
Script on netsnmp tool (todo)

Echo server and client program

Server programming with one client support at a time

#!/usr/bin/env python3
# File: echo-server.py

import socket

#HOST = '127.0.0.1'
HOST = ''
PORT = 56432


# with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as s:
sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
sock.bind((HOST, PORT))
sock.listen(1)
while True:
        print('Waiting to accpet a new connection')
        conn, addr = sock.accept()
        print('Connected by', addr)
        while True:
                data = conn.recv(1024)
                if not data:
                        break
                print('Received', repr(data))
                print('Echoing ...')
                conn.sendall(data)
        print('Closing the connection:', conn.getsockname(), conn.getpeername())
        conn.close()
sock.close()

Echo client with one send()

#!/usr/bin/env python3
# File: echo-client_v2.py

import socket

#HOST = '127.0.0.1'
HOST = '10.128.2.208'
PORT = 56433

s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.connect((HOST, PORT))
s.sendall(b'Hello, world')
data = s.recv(1024)
print('Received', repr(data))

s.close()

Server with multi-threading support

Echo server can support more than one connection at a time

#!/usr/bin/env python3
# File : echo-server_multithread.py

import socket

from _thread import *
import threading

print_lock = threading.Lock()

#thread function
def recv_func(c):
    while True:
        print_lock.acquire()
        print('[server-th]', threading.current_thread())
        print('[server-th]Waiting for data')
        print_lock.release()
        data = c.recv(1024)
        if not data:
            print_lock.acquire()
            print('[server-th] EOF: Closing the connection:', c.getsockname(), c.getpeername())
            print_lock.release()
            break

        print_lock.acquire()
        print('[server-th] Received', repr(data))
        print('[server-th] Echoing ...')
        print_lock.release()
        c.sendall(data)

    c.close()


def Main():
#HOST = '127.0.0.1'
    HOST = ''
    PORT = 56433


# with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as s:
    sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
    sock.bind((HOST, PORT))
    sock.listen(5)
    while True:
        print_lock.acquire()
        print('[Server] Waiting to accpet a new connection')
        print_lock.release()

        conn, addr = sock.accept()
        print_lock.acquire()
        print('[Server] Received connection from:', addr)
        print_lock.release()

        start_new_thread(recv_func, (conn,))

    print_lock.acquire()
    print('[Server] Closing server.')
    print_lock.release()
    sock.close()

if __name__ == '__main__':
    Main()

Client with multiple send()

#!/usr/bin/env python3

import socket
import time

#HOST = '127.0.0.1'
HOST = '10.128.2.208'
PORT = 56433

s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.connect((HOST, PORT))
counter = 0

while counter < 10:
        s.sendall(b'Hello, world: ')
        data = s.recv(1024)
        print('Received: ',counter,  repr(data))
        time.sleep(1)
        counter += 1

s.close()

Fibonacci series with CL input

#!/usr/bin/env python3
# File: fibonacci_test.py

def fibonacci_func(max):
        a, b = 0, 1

        while a < max:
                print(a, end=', ')
                a, b = b , a+b

def Main():
        max = int(input("How big Fibonacci series do you want? "))
        print(type(max))
        fibonacci_func(max)
        print(' end')

if __name__ == '__main__':
        Main()

Output

$ ./fibonacci_test.py
How big Fibonacci series do you want? 450
<class 'int'>
0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144, 233, 377,  end

Word count of a text file

#!/usr/bin/env python3

def file_op(c, dic):
        with open(c) as fp:
                for line in fp:
                        print(line)
                        words = line.split()
                        print('[word-count in the above line]', len(words))
                        print('Words', words)
                        for word in words:
                                if word not in dic:
                                        dic[word] = 1
                                else:
                                        count = dic[word]
                                        dic[word] = count + 1

def Main():
        #myfile = 'testfile.txt'
        myfile = input("Enter the filename: ")
        dic = dict()
        file_op(myfile, dic)
        print('Word count in the file \n\t : ', dic)

if __name__ == '__main__':
        Main()

Output

./work-with-file.py
Enter the filename: testfile.txt
This is a test file

[word-count in the above line] 5
Words ['This', 'is', 'a', 'test', 'file']
This has few lines

[word-count in the above line] 4
Words ['This', 'has', 'few', 'lines']
Count the lines and

[word-count in the above line] 4
Words ['Count', 'the', 'lines', 'and']
duplicate words.

[word-count in the above line] 2
Words ['duplicate', 'words.']
Word count in the file
         :  {'a': 1, 'Count': 1, 'and': 1, 'words.': 1, 'This': 2, 'is': 1, 'lines': 2, 'few': 1, 'duplicate': 1, 'file': 1, 'test': 1, 'the': 1, 'has': 1}

Format example in print

#!/usr/bin/env python3

def format_type1(r):
        for x in r:
                print('{0:2d} {1:3d} {2:4d}'.format(x, x*x, x*x*x))

def format_type2_up(m):
        o = 0
        for x in range(0, m+1):
                pos = m+1
                iter = (x*2)+1
                #print('x: {0}, pos: {1} , iter: {2}'.format(x, pos, iter))
                first = 1
                for y in range(0, iter):
                        if first == 1:
                                pos = pos - x
                                print(repr(o).rjust(pos), end='')
                                first = 0
                        else:
                                print('{0}'.format(o), end='')
                print()


def format_type2_down(m):
        o = 1
        for x in reversed(range(0, m+1)):
                pos = m+1
                iter = (x*2)+1
                #print('x: {0}, pos: {1} , iter: {2}'.format(x, pos, iter))
                first = 1
                for y in range(0, iter):
                        if first == 1:
                                pos = pos - x
                                print(repr(o).rjust(pos), end='')
                                first = 0
                        else:
                                print('{0}'.format(o), end='')
                print()

def Main():
        Mx = int(input("Enter size: "))
        print('Format:1 ')
        format_type1(range(1, Mx+1))
        print('Format:2 ')
        format_type2_up(Mx)
        print('Format:3 ')
        format_type2_down(Mx)

if __name__=='__main__':
        Main()

Output

./formatting-output.py
Enter size: 10
Format:1
 1   1    1
 2   4    8
 3   9   27
 4  16   64
 5  25  125
 6  36  216
 7  49  343
 8  64  512
 9  81  729
10 100 1000
Format:2
          0
         000
        00000
       0000000
      000000000
     00000000000
    0000000000000
   000000000000000
  00000000000000000
 0000000000000000000
000000000000000000000
Format:3
111111111111111111111
 1111111111111111111
  11111111111111111
   111111111111111
    1111111111111
     11111111111
      111111111
       1111111
        11111
         111
          1

Class example

#!/usr/bin/env python3

class Dog:

        def __init__(self, name):
                self.name = name
                self.tricks = []

        def add_trick(self, trick):
                self.tricks.append(trick)

def Main():
        name1= input("Enter name of dog1: ")
        name2= input("Enter name of dog2: ")

        d = Dog(name1)
        e = Dog(name2)

        d.add_trick('fast in jumping')
        e.add_trick('lazy')

        print('Tricks for {0}: {1},and  tricks for {2}: {3}'.format(d.name, d.tricks, e.name, e.tricks))

if __name__=='__main__':
        Main()

self, init, call

self: calling members of own class
__init__: constructor
 
class Foo:
    def __init__(self, a, b, c):
        # ...
 
x = Foo(1, 2, 3) # __init__
 
__call__: implements function call operator.
class Foo:
    def __call__(self, a, b, c):
        # ...
 
x = Foo()
x(1, 2, 3) # __call__

Super, Inheritance, multiple inheritance and MRO (method resolution order)

Refer : https://www.programiz.com/python-programming/methods/built-in/super

class Animal:
  def __init__(self, animalName):
    print(animalName, 'is an animal.');
class Mammal(Animal):
  def __init__(self, mammalName):
    print(mammalName, 'is a warm-blooded animal.')
    super().__init__(mammalName)
     
class NonWingedMammal(Mammal):
  def __init__(self, NonWingedMammalName):
    print(NonWingedMammalName, "can't fly.")
    super().__init__(NonWingedMammalName)
class NonMarineMammal(Mammal):
  def __init__(self, NonMarineMammalName):
    print(NonMarineMammalName, "can't swim.")
    super().__init__(NonMarineMammalName)
class Dog(NonMarineMammal, NonWingedMammal):
  def __init__(self):
    print('Dog has 4 legs.');
    super().__init__('Dog')
     
d = Dog()
print('')
bat = NonMarineMammal('Bat')

try, except, else and finally

https://www.w3schools.com/python/python_try_except.asp

try:
  print(x)
except NameError:
  print("Variable x is not defined")
except:
  print("Something else went wrong")

Python Libraries

Requests library

import requests

paga_name = requests.get('http://www.google.com')

print(paga_name)

///output
<Response [200]>

SciKit learn : to build a machine learning model

from sklearn import datasets, neighbors, linear_model

digits = datasets.load_digits()
X_digits = digits.data / digits.data.max()
y_digits = digits.target

n_samples = len(X_digits)

X_train = X_digits[:int(.9 * n_samples)]
y_train = y_digits[:int(.9 * n_samples)]
X_test = X_digits[int(.9 * n_samples):]
y_test = y_digits[int(.9 * n_samples):]

knn = neighbors.KNeighborsClassifier()
logistic = linear_model.LogisticRegression(solver='lbfgs', max_iter=1000,
                                           multi_class='multinomial')

print('KNN score: %f' % knn.fit(X_train, y_train).score(X_test, y_test))
print('LogisticRegression score: %f'
      % logistic.fit(X_train, y_train).score(X_test, y_test))

//output
KNN score: 0.961111
LogisticRegression score: 0.933333

import numpy as np
import matplotlib.pyplot as plt
from matplotlib.collections import LineCollection

from sklearn.linear_model import LinearRegression
from sklearn.isotonic import IsotonicRegression
from sklearn.utils import check_random_state

n = 100
x = np.arange(n)
rs = check_random_state(0)
y = rs.randint(-50, 50, size=(n,)) + 50. * np.log1p(np.arange(n))

# #############################################################################
# Fit IsotonicRegression and LinearRegression models

ir = IsotonicRegression()

y_ = ir.fit_transform(x, y)

lr = LinearRegression()
lr.fit(x[:, np.newaxis], y)  # x needs to be 2d for LinearRegression

# #############################################################################
# Plot result

segments = [[[i, y[i]], [i, y_[i]]] for i in range(n)]
lc = LineCollection(segments, zorder=0)
lc.set_array(np.ones(len(y)))
lc.set_linewidths(np.full(n, 0.5))

fig = plt.figure()
plt.plot(x, y, 'r.', markersize=12)
plt.plot(x, y_, 'b.-', markersize=12)
plt.plot(x, lr.predict(x[:, np.newaxis]), 'b-')
plt.gca().add_collection(lc)
plt.legend(('Data', 'Isotonic Fit', 'Linear Fit'), loc='lower right')
plt.title('Isotonic regression')
plt.show()

Python Coding

Contents

Echo server and client program

Server with multi-threading support

Fibonacci series with CL input

Output

Word count of a text file

Output

Format example in print

Output

Class example

self, init, call

Super, Inheritance, multiple inheritance and MRO (method resolution order)

try, except, else and finally

Python Libraries

Requests library

SciKit learn : to build a machine learning model

Published by nsarkar007

Leave a comment Cancel reply

Contents

Echo server and client program

Server with multi-threading support

Fibonacci series with CL input

Output

Word count of a text file

Output

Format example in print

Output

Class example

self, __init__, __call__

Super, Inheritance, multiple inheritance and MRO (method resolution order)

try, except, else and finally

Python Libraries

Requests library

SciKit learn : to build a machine learning model

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Related

Published by nsarkar007

Leave a comment Cancel reply

self, init, call