Generate prime numbers and set operations

Sets

• Set is a mutable and an unordered collection of elements without duplicates.
• That means the elements within a set cannot be repeated.
• This feature used to include membership testing and eliminating duplicate elements.

Creating a Set

• A set is created by placing all the elements separated by comma within a pair of curly brackets.
• The set( ) function can also used to create sets in Python.

Creating Set using List or Tuple

• A list or Tuple can be converted as set by using set( ) function.
• This is very simple procedure.
• First you have to create a list or Tuple then, substitute its variable within set( ) function as argument.

Set Operations

• The python is also supports the set operations such as Union, Intersection, difference and Symmetric difference.

Union:

• It includes all elements from two or more sets

Intersection:

• It includes the common elements in two sets
• Th e operator & is used to intersect two sets in python.
• The function intersection( ) is also used to intersect two sets in python.

Difference

• It includes all elements that are in first set (say set A) but not in the second set (say set B)

Symmetric difference

• It includes all the elements that are in two sets (say sets A and B) but not the one that are common to two sets.

Note:

• When you print the elements from a set, python shows the values in different order.

Prime Numbers:

• Prime number can be divisible by single factor
• 2,3,5,7 example for prime numbers

for loop

• for loop is the most comfortable loop. It is also an entry check loop.
• The condition is checked in the beginning and the body of the loop(statements-block 1) is executed if it is only True otherwise the loop is not executed.
• The counter_variable mentioned in the syntax is similar to the control variable that weused in the for loop of C++ and the sequence refers to the initial, final and increment value.
• Usually in Python, for loop uses the range() function in the sequence to specify the initial, final
  and increment values.
• range() generates a list of values starting from start till stop-1.

Syntax:

for counter_variable in sequence:
statements-block 1
[else: # optional block
statements-block 2]

The syntax of range() is as follows:

range (start,stop,[step])
Where,
start – refers to the initial value
stop – refers to the final value
step – refers to increment value, this is optional part.

PY 4 – GENERATE PRIME NUMBERS AND SET OPERATIONS

QUESTION:

• Write a Program that generates a set of prime numbers and another set of odd numbers.
• Display the result of union, intersection, difference and symmetric difference operations.

AIM:

• To generate a set of prime numbers and another set of odd numbers, and to display the result of union, intersection, difference and symmetric difference operations.

CODING:

odd=set([x*2+1 for x in range (0,5)])
primes=set()
for i in range(2,10):
j=2
f=0
while j<=i/2:
if i%j==0:
f=1
j+=1
if f==0:
primes.add(i)
print(“odd number:”, odd)
print(“prime number:”, primes)
print(“union:”, odd.union(primes))
print(“intersection:”, odd.intersection(primes))
print(“difference:”, odd.difference(primes))
print(“symmetric difference:”, odd.symmetric_difference(primes))

OUTPUT:

odd number: {1, 3, 5, 7, 9}
prime number: {2, 3, 5, 7}
union: {1, 2, 3, 5, 7, 9}
intersection: {3, 5, 7}
difference: {1, 9}
symmetric difference: {1, 2, 9}