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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 occurrenceTuples: tuples are immutable! |
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Concatenate two lists or two tuples?
Lists:
myList1 + myList2Tuples: myTuple1 + myTuple2Concatenating 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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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 KeyErorrMethod 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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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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