## Sets

• Sets are unordered collection of unique objects and is used find distinct values or manage problems related to membership
• To create a set a collection of values in curly braces or give an existing collection item to set() • Set Operations
• clear
• copy
• difference
• intersection
• union
• issubset
• issuperset ## Dicitionary

• Dictionary is mapping between keys and values.
• We can create dictionary by closing keys and values with in curly braces
``````stock = {
'name' : 'Microsoft',
'price': 286.54
}
``````
• To access the elements we can access them by keys
``````stock['name']
stock['price']
`````` • Iterating a dictionary
``````portfolio = dict()
portfolio['Microsoft'] = 286.54
portfolio['IBM'] = 142.75
portfolio['Amazon'] = 3626.39
portfolio['Apple'] = 146.77

for name, price in portfolio.items():
print(f"{name} ==> {price}")

for name in portfolio.keys():
print(f"{name} --> {portfolio[name]}")
``````

## Range in python

• Generally when we iterate over a loop we iterate over a range of integers, Python has a range function that create an object that represents range of integers.
``````range(start, stop [,step])
``````
• Examples
``````range(5)  => 0,1,2,3,4
range(1,6) => 1,2,3,4,5
range(0,10,3) => 0,3,6,9
range(5,1,-1) => 5,4,3,2
``````
• Lets use this range with for loop to find the prime number
• With while
``````number = 19
index = 2
while index < number:
if number%index == 0:
print('not prime')
break
index += 1
else:
print('prime')
``````
• With Range
``````number = 19
for index in range(2,19):
if number%index == 0:
print('not prime')
break
else:
print('prime')
``````

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