COMP10001 Lecture 4: Week 4
25 May 2018
School
Department
Course
Professor
Use [ , ]
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Mutable
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Can use indexing, slice, calculate length
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Via assignment
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.append() = add item to end
.remove() = remove first instance of a given value
.pop() = remove element of given index value
.sort() = sort contents
Via methods
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Modify the internals of lists
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Lists:
mydict = {"a": 1, "b": 2}
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dictionary[key] = value to add items to a dictionary
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mydict[key] to access item
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x = dictionary.pop(key) to delete items from a dictionary
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key in mydict to test for key membership
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mydict.clear() to delete the entire contents
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del mydict[key] to delete an entry without a return value
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mydict.keys() to see keys
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mydict.values() to see values
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mydict.items() to see (key,val)
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Dictionaries:
sets are like dictionaries without keys
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a
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b = set difference
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a | b = set union
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a & b = set intersection
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mutable with .add() and .remove()
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.intersection()
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.intersection_update()
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.difference()
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.difference_update()
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Sets:
keys in dictionaries and elements in sets must be "hashable"
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int
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float
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str
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tuple
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bool
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immutable built
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in objects are hashable
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list, dict, set cannot be keys or elements
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Hashable:
Week 4
Saturday, 24 March 2018 5:53 PM
Foundations of Computing Page 1
