Add basic Python programs covering core concepts

.gitignore

@@ -21,3 +21,4 @@
 npm-debug.log*
 yarn-debug.log*
 yarn-error.log*
+.appmodconfig

python123/P01_hello.py

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+# Author: OMKAR PATHAK
+# This program prints the entered message
+
+def print_text(text):
+    '''This function prints the text passed as argument to this function'''
+    print(text)
+
+if __name__ == '__main__':
+    print_text('Hello01 appmod')

python123/P02_InstanceMethods.py

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+#Author: OMKAR PATHAK
+#In this example we will be seeing how instance methods are used
+#Instance methods are accessed by: instance.method()
+
+class Vehicle():
+    #Class Methods/ Attributes
+
+    #Here self is passed as an argument because instance is passed as first argument
+    def get_vehicle_type(self):
+        print(self)
+        print('I have a type')
+
+car = Vehicle()
+print(car)
+car.type()

python123/P02_VariableScope copy.py

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+#Author: OMKAR PATHAK
+#This programs shows the rules for variable scope
+
+# LEGB Rule: Local, Enclosing, Global, Built-in
+
+x = 80  # Global x
+
+def test():
+    #global x
+    y = 100  # Local y
+    x = 20
+    print(x + y) #prints 'Local x' and  'Local y'
+
+if __name__ == '__main__':
+    test()
+    print(x) #prints 'Global x'

python123/P05_Pattern.py

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+#Author: OMKAR PATHAK
+#This program prints various patterns
+
+def pattern1(level):
+    '''This function prints the following pattern:
+
+    *
+    **
+    ***
+    ****
+
+    '''
+    for i in range(1, level + 1):
+        print()
+        for j in range(i):
+            print('*', end = '')
+
+def pattern2(level):
+    '''This function prints the following pattern:
+
+    ****
+    ***
+    **
+    *
+
+    '''
+    for i in range(level, 0, -1):
+        print()
+        for j in range(i):
+            print('*', end = '')
+
+def pattern3(level):
+    '''This function prints the following pattern:
+
+       *
+      **
+     ***
+    ****
+
+    '''
+    counter = level
+    for i in range(level + 1):
+        print(' ' * counter + '*' * i)
+        counter -= 1
+
+def pattern4(level):
+    '''This function prints the following pattern:
+
+    ****
+     ***
+      **
+       *
+
+    '''
+    counter = 0
+    for i in range(level, 0 ,-1):
+        print(' ' * counter + '*' * i)
+        counter += 1
+
+def pattern5(level):
+    '''This function prints the following pattern:
+
+      *
+     ***
+    *****
+
+    '''
+    # first loop for number of lines
+    for i in range(level + 1):
+        #second loop for spaces
+        for j in range(level - i):
+            print (" ",end='')
+        # this loop is for printing stars
+        for k in range(2 * i - 1):
+            print("*", end='')
+        print()
+
+
+if __name__ == '__main__':
+    userInput = int(input('Enter the level: '))
+    pattern1(userInput)
+    print()
+    pattern2(userInput)
+    print()
+    pattern3(userInput)
+    print()
+    pattern4(userInput)
+    print()
+    pattern5(userInput)
+    print()
+
+    def pattern6(userInput):
+        '''
+        following is the another approach to solve pattern problems with reduced time complexity 
+
+        for 
+
+        *
+        **
+        ***
+        ****
+        *****
+        '''
+
+        num = int(input('Enter number for pattern'))
+        pattern = '*'
+        string = pattern * num
+        x = 0
+
+        for i in string:
+            x = x + 1
+            print(string[0:x])

python123/P06_CharCount.py

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+#Author: OMKAR PATHAK
+#This program checks for the character frequency in the given string
+
+def charFrequency(userInput):
+    '''This fuction helps to count the char frequency in the given string '''
+    userInput = userInput.lower() #covert to lowercase
+    dict = {}
+    for char in userInput:
+        keys = dict.keys()
+        if char in keys:
+            dict[char] += 1
+        else:
+            dict[char] = 1
+    return dict
+
+if __name__ == '__main__':
+    userInput = str(input('Enter a string: '))
+    print(charFrequency(userInput))

python123/P06_Inheritance.py

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+#Author: OMKAR PATHAK
+#This program illustrates the concept of inheritance
+#Python looks up for method in following order: Instance attributes, class attributes and the
+#from the base class
+
+class Data(object):
+    def getData(self):
+        print('In data!')
+
+class Time(Data):           #Inheriting from Data class
+    def getTime(self):
+        print('In Time!')
+
+if __name__ == '__main__':
+    data = Data()
+    time = Time()
+
+    data.getData()
+    time.getTime()
+    time.getData()          #Inherited Data method

python123/P07_MoreOnInheritance.py

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+#Author: OMKAR PATHAK
+#This program illustrates the advanced concepts of inheritance
+#Python looks up for method in following order: Instance attributes, class attributes and the
+#from the base class
+#mro: Method Resolution order
+
+class Data(object):
+    def __init__(self, data):
+        self.data = data
+
+    def getData(self):
+        print('Data:',self.data)
+
+class Time(Data):           #Inhertiting from Data class
+    def getTime(self):
+        print('Time:',self.data)
+
+if __name__ == '__main__':
+    data = Data(10)
+    time = Time(20)     #inherited Class -> Value passed to __init__of Data (Base class)
+
+    time.getTime()
+    data.getData()
+    time.getData()
+
+    print(Time.mro())

python123/P07_PrimeNumber.py

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+#Author: OMKAR PATHAK
+#This program checks whether the entered number is prime or not
+
+def checkPrime(number):
+    '''This function checks for prime number'''
+    isPrime = False
+    if number == 2:
+        print(number, 'is a Prime Number')
+    if number > 1:
+        for i in range(2, number):
+            if number % i == 0:
+                print(number, 'is not a Prime Number')
+                isPrime = False
+                break
+            else:
+                isPrime = True
+
+        if isPrime:
+            print(number, 'is a Prime Number')
+
+if __name__ == '__main__':
+    userInput = int(input('Enter a number to check: '))
+    checkPrime(userInput)

python123/P50_ListComprehensions.py

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+# Author: OMKAR PATHAK
+# In this example we will see how to write list comprehensions to make our tasks easier
+
+# Python.org says:
+# List comprehensions provide a concise way to create lists.
+# Common applications are to make new lists where each element is
+# the result of some operations applied to each member of another sequence
+# or iterable, or to create a subsequence of those elements that satisfy a certain condition.
+
+numbers = []
+for i in range(10):
+    numbers.append(i)
+print(numbers)              # [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
+
+# Side Effect of above operation:It creates a variable(or overwrites) named 'x'
+# that still exists after the loop completes. To get rid of this Side Effect we use List comprehensions.
+
+# List comprehension:
+numbers = [i for i in range(10)]
+print(numbers)              # [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
+
+# Let us see few more examples
+squares = [i * i for i in range(10)]
+print(squares)              # [0, 1, 4, 9, 16, 25, 36, 49, 64, 81]
+
+# This is same as:
+squares = []
+for i in range(10):
+    squares.append(i * i)
+
+# Some more:
+odds = [i for i in numbers if i % 2 != 0]
+print(odds)                 # [1, 3, 5, 7, 9]
+
+# This is same as:
+odds = []
+for i in numbers:
+    if i % 2 != 0:
+        odds.append(i)
+
+# We can also use functions in comprehensions
+def isSqaure(x):
+    import math
+    sqrt = int(math.sqrt(x))
+    return x == sqrt * sqrt
+
+squares = [x for x in range(100) if isSqaure(x) == True]
+print(squares)             # [0, 1, 4, 9, 16, 25, 36, 49, 64, 81]
+
+# Some Complex comprehensions:
+pairs = [[x, x * x] for x in numbers]
+print(pairs)               # [[0, 0], [1, 1], [2, 4], [3, 9], [4, 16], [5, 25], [6, 36], [7, 49], [8, 64], [9, 81]]

python123/P51_PythonJSON.py

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+# Author: OMKAR PATHAK
+# This example shows how to use Python with JSON
+
+import json
+
+# For storing on json format
+def storeJSON(fileName, data=None):
+    with open(fileName, 'w')  as fd:
+        json.dump(data, fd, indent = 4, separators = (',', ': '))
+
+# For loading data from a JSON file
+def loadJSON(fileName):
+    with open(fileName) as fd:
+        data = json.load(fd)
+        print(data)
+    return data
+
+if __name__ == '__main__':
+    data = loadJSON('example.json')
+    print(data['menu']['value'])        # File
+    data['menu']['value'] = 'movie'
+    storeJSON('example.json', data)
+    print()
+    loadJSON('example.json')
+    print(data['menu']['value'])        # movie

python123/P52_BucketSort.py

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+# Author: OMKAR PATHAK
+# This program will illustrate how to implement bucket sort algorithm
+
+# Wikipedia says: Bucket sort, or bin sort, is a sorting algorithm that works by distributing the
+# elements of an array into a number of buckets. Each bucket is then sorted individually, either using 
+# a different sorting algorithm, or by recursively applying the bucket sorting algorithm. It is a
+# distribution sort, and is a cousin of radix sort in the most to least significant digit flavour.
+# Bucket sort is a generalization of pigeonhole sort. Bucket sort can be implemented with comparisons
+# and therefore can also be considered a comparison sort algorithm. The computational complexity estimates
+# involve the number of buckets.
+
+#  Time Complexity of Solution:
+#  Best Case O(n); Average Case O(n); Worst Case O(n)
+
+from P26_InsertionSort import insertionSort
+import math
+
+DEFAULT_BUCKET_SIZE = 5
+
+def bucketSort(myList, bucketSize=DEFAULT_BUCKET_SIZE):
+    if(len(myList) == 0):
+        print('You don\'t have any elements in array!')
+
+    minValue = myList[0]
+    maxValue = myList[0]
+
+    # For finding minimum and maximum values
+    for i in range(0, len(myList)):
+        if myList[i] < minValue:
+            minValue = myList[i]
+        elif myList[i] > maxValue:
+            maxValue = myList[i]
+
+    # Initialize buckets
+    bucketCount = math.floor((maxValue - minValue) / bucketSize) + 1
+    buckets = []
+    for i in range(0, bucketCount):
+        buckets.append([])
+
+    # For putting values in buckets
+    for i in range(0, len(myList)):
+        buckets[math.floor((myList[i] - minValue) / bucketSize)].append(myList[i])
+
+    # Sort buckets and place back into input array
+    sortedArray = []
+    for i in range(0, len(buckets)):
+        insertionSort(buckets[i])
+        for j in range(0, len(buckets[i])):
+            sortedArray.append(buckets[i][j])
+
+    return sortedArray
+
+if __name__ == '__main__':
+    sortedArray = bucketSort([12, 23, 4, 5, 3, 2, 12, 81, 56, 95])
+    print(sortedArray)