Python PCEP Tuples and Dictionaries

Python PCEP Tuples and Dictionaries

• 1.
  Tuples and dictionaries Module3 Functions, Tuples, Dictionaries, Data processing
• 2.
  Module 3 Tuplesand dictionaries Sequence types & mutability sequence types • is a type of data • is data which can be scanned by the for loop 2 kinds of Python data • Mutable data can be freely updated at any time • Immutable data cannot be modified in this way
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  Module 3 Tuplesand dictionaries What is a tuple? tuple_1 = (1, 2, 4, 8) tuple_2 = 1., .5, .25, .125 print(tuple_1) print(tuple_2) (1, 2, 4, 8) (1.0, 0.5, 0.25, 0.125) create a tuple empty_tuple = () one_element_tuple_1 = (1, )
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  Module 3 Tuplesand dictionaries Do not modify tuple's contents! my_tuple = (1, 10, 100, 1000) print(my_tuple[0]) print(my_tuple[-1]) print(my_tuple[1:]) print(my_tuple[:-2]) for elem in my_tuple: print(elem) 1 1000 (10, 100, 1000) (1, 10) 1 10 100 1000 my_tuple = (1, 10, 100, 1000) my_tuple.append(10000) del my_tuple[0] my_tuple[1] = -10 print(my_tuple) AttributeError: 'tuple' object has no attribute 'append'
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  Module 3 Tuplesand dictionaries How to use a tuple my_tuple = (1, 10, 100) t1 = my_tuple + (1000, 10000) t2 = my_tuple * 3 print(len(t2)) print(t1) print(t2) print(10 in my_tuple) print(-10 not in my_tuple) 9 (1, 10, 100, 1000, 10000) (1, 10, 100, 1, 10, 100, 1, 10, 100) True True var = 123 t1 = (1, ) t2 = (2, ) t3 = (3, var) t1, t2, t3 = t2, t3, t1 print(t1, t2, t3) (2,) (3, 123) (1,)
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  Module 3 Tuplesand dictionaries What is a dictionary? each key must be unique a key may be any immutable type of object a dictionary holds pairs of values the len() function works for dictionaries a dictionary is a one-way tool
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  Module 3 Tuplesand dictionaries How to make a dictionary? dictionary = {"cat": "chat", "dog": "chien", "horse": "cheval"} phone_numbers = {'boss': 5551234567, 'Suzy': 22657854310} empty_dictionary = {} print(dictionary['cat']) print(phone_numbers['Suzy']) chat 22657854310 dictionary = { "cat": "chat", "dog": "chien", "horse": "cheval" } words = ['cat', 'lion', 'horse'] for word in words: if word in dictionary: print(word, "->", dictionary[word]) else: print(word, "is not in dictionary") cat -> chat lion is not in dictionary horse -> cheval
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  Module 3 Tuplesand dictionaries keys(), sorted() dictionary = {"cat": "chat", "dog": "chien", "horse": "cheval"} for key in dictionary.keys(): print(key, "->", dictionary[key]) horse -> cheval dog -> chien cat -> chat dictionary = {"cat": "chat", "dog": "chien", "horse": "cheval"} for key in sorted(dictionary.keys()): print(key, "->", dictionary[key]) cat -> chat dog -> chien horse -> cheval
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  Module 3 Tuplesand dictionaries items() & values() methods dictionary = {"cat": "chat", "dog": "chien", "horse": "cheval"} for english, french in dictionary.items(): print(english, "->", french) cat -> chat dog -> chien horse -> cheval dictionary = {"cat": "chat", "dog": "chien", "horse": "cheval"} for french in dictionary.values(): print(french) cheval chien chat
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  Module 3 Tuplesand dictionaries Modifying and adding values dictionary = {"cat": "chat", "dog": "chien", "horse": "cheval"} dictionary['cat'] = 'minou' print(dictionary) {'cat': 'minou', 'dog': 'chien', 'horse': 'cheval'} dictionary = {"cat": "chat", "dog": "chien", "horse": "cheval"} dictionary['swan'] = 'cygne' print(dictionary) {'cat': 'chat', 'dog': 'chien', 'horse': 'cheval', 'swan': 'cygne'}
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  Module 3 Tuplesand dictionaries Tuples and dictionaries • you need a program to evaluate the students' average scores; • the program should ask for the student's name, followed by her/his single score; • the names may be entered in any order; • entering an empty name finishes the inputting of the data; • a list of all names, together with the evaluated average score, should be then emitted. school_class = {} while True: name = input("Enter the student's name: ") if name == '': break score = int(input("Enter the student's score (0-10): ")) if score not in range(0, 11): break if name in school_class: school_class[name] += (score,) else: school_class[name] = (score,) for name in sorted(school_class.keys()): adding = 0 counter = 0 for score in school_class[name]: adding += score counter += 1 print(name, ":", adding / counter)
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  Module 3 Tuplesand dictionaries Key takeaways: tuples Tuples are ordered and unchangeable (immutable) collections of data. You can create an empty tuple, one-element tuple. You can access tuple elements by indexing them. Tuples are immutable, which means you cannot change their elements You can loop through a tuple elements .
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  Module 3 Tuplesand dictionaries EXTRA: tuple(), list() my_tuple = tuple((1, 2, "string")) print(my_tuple) my_list = [2, 4, 6] print(my_list) # outputs: [2, 4, 6] print(type(my_list)) # outputs: <class 'list'> tup = tuple(my_list) print(tup) # outputs: (2, 4, 6) print(type(tup)) # outputs: <class 'tuple'> tup = 1, 2, 3, my_list = list(tup) print(type(my_list)) # outputs: <class 'list'>
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  Module 3 Tuplesand dictionaries Key takeaways: dictionaries 1 Dictionaries are unordered*, changeable (mutable), and indexed collections of data. If you want to access a dictionary item: pol_eng_dictionary = {"kwiat": "flower","woda": "water","gleba": "soil"} item_1 = pol_eng_dictionary["gleba"] # ex. 1 print(item_1) # outputs: soil item_2 = pol_eng_dictionary.get("woda") print(item_2) # outputs: water
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  Module 3 Tuplesand dictionaries Key takeaways: dictionaries 2 If you want to change the value associated with a specific key: To add or remove a key (and the associated value): pol_eng_dictionary = {"kwiat": "flower","woda": "water","gleba": "soil"} pol_eng_dictionary["zamek"] = "lock" item = pol_eng_dictionary["zamek"] print(item) # outputs: lock phonebook = {} # an empty dictionary phonebook["Adam"] = 3456783958 # create/add a key-value pair print(phonebook) # outputs: {'Adam': 3456783958} del phonebook["Adam"] print(phonebook) # outputs: {}
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  Module 3 Tuplesand dictionaries Key takeaways: dictionaries 3 You can use the for loop to loop through a dictionary: pol_eng_dictionary = {"kwiat": "flower"} pol_eng_dictionary.update({"gleba": "soil"}) print(pol_eng_dictionary) # outputs: {'kwiat': 'flower', 'gleba': 'soil'} pol_eng_dictionary.popitem() print(pol_eng_dictionary) # outputs: {'kwiat': 'flower'} pol_eng_dictionary = {"kwiat": "flower","woda": "water","gleba": "soil"} for item in pol_eng_dictionary: print(item) # outputs: zamek # woda # gleba
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  Module 3 Tuplesand dictionaries Key takeaways: dictionaries 4 If you want to loop through a dictionary's keys and values: pol_eng_dictionary = {"kwiat": "flower","woda": "water","gleba": "soil"} for key, value in pol_eng_dictionary.items(): print("Pol/Eng ->", key, ":", value) To check if a given key exists in a dictionary: pol_eng_dictionary = {"kwiat": "flower","woda": "water","gleba": "soil"} if "zamek" in pol_eng_dictionary: print("Yes") else: print("No")
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  Module 3 Tuplesand dictionaries Key takeaways: dictionaries 5 To remove a specific item: pol_eng_dictionary = {"kwiat": "flower","woda": "water","gleba": "soil"} print(len(pol_eng_dictionary)) # outputs: 3 del pol_eng_dictionary["zamek"] # remove an item print(len(pol_eng_dictionary)) # outputs: 2 pol_eng_dictionary.clear() # removes all the items print(len(pol_eng_dictionary)) # outputs: 0 del pol_eng_dictionary # removes the dictionary To copy a dictionary: pol_eng_dictionary = {"kwiat": "flower","woda": "water","gleba": "soil"} copy_dictionary = pol_eng_dictionary.copy()
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  Module 3 Tuplesand dictionaries LAB Practice 29. Tic-Tac-Toe
• 20.
  Congratulations! You have completedModule 3 the defining and using of functions the concept of passing arguments in different ways name scope issues tuples and dictionaries