INTRO TO CS (QUIZ #9)
What is printed by the following statements? mydict = {"cat":12, "dog":6, "elephant":23} mydict["mouse"] = mydict["cat"] + mydict["dog"] print(mydict["mouse"])
18
What is printed by the following statements? mydict = {"cat":12, "dog":6, "elephant":23, "bear":20} answer = mydict.get("cat") // mydict.get("dog") print(answer)
2
What is printed by the following statements? total = 0 mydict = {"cat":12, "dog":6, "elephant":23, "bear":20} for akey in mydict: if len(akey) > 3: total = total + mydict[akey] print(total)
43
What is printed by the following statements? mydict = {"cat":12, "dog":6, "elephant":23} print(mydict["dog"])
6
What is printed by the following statements? mydict = {"cat":12, "dog":6, "elephant":23, "bear":20} yourdict = mydict yourdict["elephant"] = 999 print(mydict["elephant"])
999
dictionary
A collection of key-value pairs that maps from keys to values. The keys can be any immutable type, and the values can be any type.
key
A data item that is mapped to a value in a dictionary. Keys are used to look up values in a dictionary.
mapping type
A mapping type is a data type comprised of a collection of keys and associated values. Python's only built-in mapping type is the dictionary. Dictionaries implement the associative array abstract data type.
key-value pair
One of the pairs of items in a dictionary. Values are looked up in a dictionary by key.
What is printed by the following statements? mydict = {"cat":12, "dog":6, "elephant":23, "bear":20} keylist = list(mydict.keys()) keylist.sort() print(keylist[3])
elephant
What is printed by the following statements? mydict = {"cat":12, "dog":6, "elephant":23, "bear":20} print(23 in mydict)
false
T/F A dictionary is an unordered collection of key-value pairs
true
What is printed by the following statements? mydict = {"cat":12, "dog":6, "elephant":23, "bear":20} print("dog" in mydict)
true