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%autosave 0

Dictionary and Set

Dictionary and Set are also container type data. They can contain any data type, including other continaer type objects. Dictionary and Set are Mutable objects.

Dictionary

dictionary[key] = value will create or update the value in the dictionary.



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x = dict()  # Create empty dictionary
x[0] = 'abc'  # Create
x[0] = 'xyz'  # update
print(x[0])
print(x[1])  # No item... error



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# Dicationary which value is List
# Disctionary is enclosed with brace {}

x = {'a': ['apple', 'anaconda'], 'b': ['beatles', 'beethoven']}
x['b'].append('beegees')
print(x)



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# MCPC rehearsal problem 1

s1 = "Living John Piano"
s2 = "Bath Alice Toothbrush"

who_what_dict = dict()    # Key Where, Value (Who, What)
x = s1.split()
who_what_dict[x[0]] = x[1:]
x = s2.split()
who_what_dict[x[0]] = x[1:]

# What is in Living ?
print(who_what_dict['Living'][1])    # [0]: Who, [1]: What

Set

Set is like a dictionary without value (only key), or List of unique items.

Elements of Set can be accessed as a iterable object (can be used in for loop)
Elements of Set can not be accessed with Index, (same as Dictionary)
String, List, Tuple or other iterable object can be converted to Set



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list_x = [1, 1, 2, 2, 3, 3, 4]
set_x = set(list_x)
print(set_x)

str_x = 'this is a string'
set_x = set(str_x)
print(set_x)

print(set_x[0])   # error

Operators of Set

Product (AND), Union (OR), Exclusive OR (XOR) and Difference are supported as oprators to created evaluated Set. Super Set, Sub Set oprators returns Boolean value.

AND: &
OR: |
XOR: ^
Difference: -
Superset >
Subset <



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set_a = {1, 2, 3, 4}
set_b = {3, 4, 5, 6}

print(set_a & set_b)
print(set_a | set_b)
print(set_a ^ set_b)
print(set_a - set_b)



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set_a = {1, 2, 3, 4}
set_b = {3, 4}
set_c = {3, 4}

print (set_a > set_b)   # is set_a a superset of set_b ?
print (set_b > set_a)
print (set_b < set_a)
print (set_b >= set_c)
print (set_b > set_c)