Python Dictionary

Python Dictionary

• 1.
  Dictionary Python Built-in DataType
• 2.
  What does Dictdo? • Collection of information • Query information • Add/Update Information Dictionary Introduction
• 3.
  Initialization • aDict = {} • aDict = dict() • aDict = { “apple” : 3 “banana”: 5 } Dictionary Introduction
• 4.
  Initialization • aDict = {} • aDict = dict() • aDict = { “apple” : 3 “banana”: 5 } Key Dictionary Introduction
• 5.
  Initialization • aDict = {} • aDict = dict() • aDict = { “apple” : 3 “banana”: 5 } Key Value Dictionary Introduction
• 6.
  Query >>> aDict["apple"] 3 >>> aDict.keys() dict_keys(['apple','banana']) >>> aDict.values() dict_values([3, 5]) >>> aDict.items() dict_items([('apple', 3), ('banana', 5)]) Dictionary Introduction
• 7.
  Query • Call eachitem with for-loop statement >>> for x in aDict.keys(): ... print(x) ... apple banana Dictionary Introduction
• 8.
  Add • Directly adda item to dictionary >>> aDict {'apple': 5, 'banana': 5} >>> aDict['waterfruit'] = 8 >>> aDict {'waterfruit': 8, 'apple': 5, 'banana': 5} Dictionary Introduction
• 9.
  Update • Update the content of the dictionary • aDict.update(<dict>) • Example: >>> aDict.update({'apple':5}) >>> aDict.update({'chocolate':10}) >>> aDict {'chocolate': 10, 'apple': 5, 'banana': 5} Dictionary Introduction
• 10.
  Delete • Remove aitem from the dictionary • del aDict[“apple”] Dictionary Introduction
• 11.
  Practice • Phone book •Functions: • Print a phone number • Add a phone number • Remove a phone number • Lookup a phone number Dictionary Introduction
• 12.
  Practice def print_menu(): print('1. Print Phone Numbers') print('2. Add a Phone Number') print('3. Remove a Phone Number') print('4. Lookup a Phone Number') print('5. Quit') print() Dictionary Introduction
• 13.
  Practice numbers = {} menu_choice= 0 print_menu() while menu_choice != 5: menu_choice = int(input("Type in a number (1-5): ")) if menu_choice == 1: pass elif menu_choice == 2: pass elif menu_choice == 3: http://goo.gl/A9xDr pass elif menu_choice == 4: pass elif menu_choice != 5: print_menu() Dictionary Introduction
• 14.
  Print if menu_choice ==1: print("Telephone Numbers:") for x in numbers.keys(): print("Name: ", x, "tNumber:", numbers[x]) print() Dictionary Introduction
• 15.
  Add elif menu_choice ==2: print("Add Name and Number") name = input("Name: ") phone = input("Number: ") numbers[name] = phone Dictionary Introduction
• 16.
  Remove elif menu_choice ==3: print("Remove Name and Number") name = input("Name: ") if name in numbers: del numbers[name] else: print(name, "was not found") Dictionary Introduction
• 17.
  Lookup elif menu_choice ==4: print("Lookup Number") name = input("Name: ") if name in numbers: print("The number is", numbers[name]) else: print(name, "was not found") Dictionary Introduction