https://www.urbanpro.com/rr/992771

To print the multiplication Table

Example:

num=int(input("enter number: "))
print("the multiplication table of %d"%num)
for i in range(1,11):    
        print(num,'*',i,'=',num*i)


output:
enter number: 5
the multiplication table of 5
5 * 1 = 5
5 * 2 = 10
5 * 3 = 15
5 * 4 = 20
5 * 5 = 25
5 * 6 = 30
5 * 7 = 35
5 * 8 = 40
5 * 9 = 45

5 * 10 = 50

http://ubpro.in/686B67PcA

command line arguments in python

• the concept of passing the arguments from command line at the time of running the python program/file,that type of arguments are called command-line arguments.

• file name also taken as a one of the command line argument.

• all the command line arguments are stored into list object in the form of strings, that list object stored into the "argv" variable of sys module.

Example:

import sys

print(sys.argv)

print(len(sys.argv))

for p in sys.argv:

    print(p)

Output1:

C:\Desktop>python commandlineargument.py hai siva krishna

['commandlineargument.py', 'hai', 'siva', 'krishna']

4

commandlineargument.py

hai

siva

krishna

Output2:

C:\Desktop>python commandlineargument.py arg1 arg2 arg3

['commandlineargument.py', 'arg1', 'arg2', 'arg3']

4

commandlineargument.py

arg1

arg2

arg3

Example:

import sys

if len(sys.argv)==3:

    try:

        x=int(sys.argv[1])

        y=int(sys.argv[2])

        z=x+y

        print(z)

    except(ValueError):

        print("enter numerical values only")

else:

    print("enter two userdefined arguments only")

Output1:

C:\Desktop>python commandlineargument.py 4 5

9

Output2:

C:\Desktop>python commandlineargument1.py 4

enter two userdefined arguments only

Output3:

C:\Desktop>python commandlineargument1.py 4 abc

enter numerical values only

reduce function in python

reduce( ) support only python 2.x

reduce( ) doesn't support python 3.x

Apply function of two arguments cumulatively to the items of iterable, from left to right, so as to reduce the iterable to a single value. 

For example, 
reduce(lambda x, y: x+y, [1, 2, 3, 4, 5]) 

calculates ((((1+2)+3)+4)+5). 

The left argument - x is the accumulated value and the right argument - y is the update value from the iterable object.

x=[2,4,5,6,3]
y=reduce(lambda i,j:i+j,x)

print(y)

20

difference between is and == in python

"is" vs "=="


-------------------------





"is" expressions evaluate to True if two variables point to the same object.


"==" evaluates to True if the objects referred to by the variables are equal.









>>> a = [1, 2, 3]


>>> b = a

>>> a is b


True


>>> a == b


True

>>> c = list(a)

>>> a == c


True


>>> a is c


False

Switch case implementation in python

Example:

def calculator(operator, x, y):
    if operator == 'add':
        return x + y
    elif operator == 'sub':
        return x - y
    elif operator == 'mul':
        return x * y
    elif operator == 'div':
        return x / y
    else:
        return None

print(calculator('add',2,3))
print(calculator('div',6,2))
print(calculator('mod',4,2))

Output:

5
3.0

None


Example: by using dict

def calculator(operator, x, y):
    return {
        'add': lambda: x + y,
        'sub': lambda: x - y,
        'mul': lambda: x * y,
        'div': lambda: x / y,
    }.get(operator, lambda: None)()

print(calculator('add',2,3))
print(calculator('div',6,2))

print(calculator('mod',4,2))

Output:

5
3.0
None