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Lists and Tuples
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What are lists and tuples? Ordered sequence of values indexed by integer numbers. Tuples are immutable.
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How to initialize an empty list/tuple? Lists: myList = []
Tuples: myTuple = ()
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Size of list/tuple? len(myListOrTuple)
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Get element in position x of list/tuple? myListOrTuple[x] -- if not found, throws IndexError
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Is element "x" in list/tuple? "x" in myListOrTuple
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Index of element "X" of list/tuple? myListOrTuple.index("x") -- If not found, throws a ValueError exception
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Number of occurrences of "x" in list/tuple? myListOrTuple.count("x")
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Update an item of a list/tuple? Lists: myList[x] = "x"
Tuples: tuples are immutable!
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Remove element in position x of list/tuple? Lists: del myList[x]
Tuples: tuples are immutable!
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Remove element "x" of a list/tuple? Lists: myList.remove("x"). Removes the first occurrence
Tuples: tuples are immutable!
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Concatenate two lists or two tuples? Lists: myList1 + myList2
Tuples: myTuple1 + myTuple2
Concatenating a List and a Tuple will produce a TypeError exception
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Insert element in position x of a list/tuple? Lists: myList.insert(x, "value")
Tuples: tuples are immutable!
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Append "x" to a list/tuple? Lists: myList.append("x")
Tuples: tuples are immutable!
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Convert a list/tuple to tuple/list List to Tuple: tuple(myList)
Tuple to List: list(myTuple)
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Slicing list/tuple myListOrTuple[ind1:ind2:step] -- step is optional and may be negative
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Sets
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What is a set? Unordered collection with no duplicate elements. Sets support mathematical operations like union, intersection, difference and simmetric difference.
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Initialize an empty set mySet = set()
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Initialize a not empty set mySet = set(element1, element2...) -- Note: strings are split into their chars (duplicates are deleted). To add strings, initialize with a Tuple/List
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Add element "x" to the set mySet.add("x")
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Remove element "x" from a set Method 1: mySet.remove("x") -- If "x" is not present, raises a KeyErorr
Method 2: mySet.discard("x") -- Removes the element, if present
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Remove every element from the set mySet.clear()
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Check if "x" is in the set "x" in mySet
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Union of two sets Method 1: mySet1.union(mySet2)
Method 2: mySet1 | mySet2
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Intersection of two sets Method 1: mySet1.intersect(mySet2)
Method 2: mySet1 & mySet2
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Difference of two sets Method 1: mySet1.difference(mySet2)
Method 2: mySet1 - mySet2
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Simmetric difference of two sets Method 1: mySet1.symmetric_difference(mySet2)
Method 2: mySet1 ^ mySet2
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Size of the set len(mySet)
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Dictionaries
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What is a dictionary? Unordered set of key:value pairs . Members are indexed by keys (immutable objects)
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Initialize an empty Dict myDict = {}
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Add an element with key "k" to the Dict myDict["k"] = value
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Update the element with key "k" myDict["k"] = newValue
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Get element with key "k" myDict["k"] -- If the key is not present, a KeyError is raised
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Check if the dictionary has key "k" "k" in myDict
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Get the list of keys myDict.keys()
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Get the size of the dictionary len(myDict)
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Delete element with key "k" from the dictionary del myDict["k"]
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Delete all the elements in the dictionary myDict.clear()
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