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