3. If Statements - LAC

Lecture notes

• Read Python Crash Course Chapter 5
• Boolean is something that is either “true” or “false” named after the English mathematician George Boole)
  checkme = True
checked = False
a == b vocab.insert('another')
• Some more useful facts about Booleans
  • Most types have a value that evaluates to false
    "", [], (), {}, …
    You can take advantage of this to make programs easier to read
• You can include a test in a list comrehension:
  [fun(w) for w in V if p(w)]
• Cheat Sheet: if/while, Cheat Sheet: if/while BW

Before class (code, output)

• Print 5 python statements that evaluate to True and 5 to False. Try to use different comparison operators (not just == but also !=, >, …
  Format like this
  print(f"1+1 == 2 {1+1 == 2}")
• Write code to check if 3 is in range(0,3).
• How can you change the range to include 3?
• Write an if - elif - else chain that determines a person’s stage of life. Set a value for the variable age, and then:
  • If the person is less than 2 years old, print a message that the person is a baby.
  • If the person is at least 2 years old but less than 4, print a message that the person is a toddler.
  • If the person is at least 4 years old but less than 8, print a message that the person is an infant.
  • If the person is at least 8 years old but less than 13, print a message that the person is a child.
  • If the person is at least 13 years old but less than 20, print a message that the person is a teenager.
  • If the person is at least 20 years old, print a message that the person is an adult.

Some problems adapted from PCC 5-6

Practical work (code, output)

• Make a tuple of person = (name, age)
• Adjust the code you wrote before class to print a personalized message based on the name and age:
  e.g. Fanny is a baby: Sleep well!
  e.g. Fran is a teenager: Enjoy School!
  e.g. Francis is an adult: Work hard!
• Take your guest list from last week, and change it to a list of tuples: [(name, age), (name, age), …]
  • use list comprehension to make a list of just the ages
  • use sum() and len() to find the average
  • Divide the guests into two groups, younger and older, depending on their age
  • Print the names of the youngest and oldest guests
• Czech numbers from 11 to 20 are semi-regularly derived from the numbers from 1 to 10. Loop through the numbers from 1 to 10 and print out that number and that plus 10.
  e.g.: jeden - jedenact

   
      čislo = ["jeden", "dva", "tři", "čtyři", "pět", "šest", "sedm", "osm", "devět", "deset"]
     

  use if - elif - else to construct the number plus 10
  the teens are: ["jedenáct", "dvanáct", "třináct", "čtrnáct", "patnáct", "šestnáct", "sedmnáct", "osmnáct", "devatenáct", "dvacet"]
• Here are some examples of Onomatopoeia:

  data = [
      # Korean Onomatopoeia
      [
          ("개굴개굴", "gaegul-gaegul", "Ribbit (frog sound)"),
          ("멍멍", "meong-meong", "Woof (dog barking)"),
          ("야옹", "ya-ong", "Meow (cat sound)"),
          ("딸랑딸랑", "ddal-lang-ddal-lang", "Jingle (bell sound)"),
      ],
      
      # Chinese Onomatopoeia
      [
          ("汪汪", "wāng wāng", "Woof (dog barking)"),
          ("喵喵", "miāo miāo", "Meow (cat sound)"),
          ("哗啦啦", "huā lā lā", "Splash (water flowing)"),
      ],
      
      # Vietnamese Onomatopoeia
      [
          ("meo meo", "", "Meow (cat sound)"),
          ("gâu gâu", "", "Woof (dog barking)"),
          ("ục ịch", "", "Splash (water or something heavy dropping in water)"),
          ("ro ro", "", "Purr (cat sound)"),
      ],
      
      # Indonesian Onomatopoeia
      [
          ("guk guk", "", "Woof (dog barking)"),
          ("meong", "", "Meow (cat sound)"),
          ("kring kring", "", "Ring (phone or bell sound)"),
      ],
      # Japanese Onomatopoeia
      [
          ("ワンワン", "wan wan", "Woof (dog barking)"),
          ("ニャーニャー", "nyaa nyaa", "Meow (cat sound)"),
          ("ピヨピヨ", "piyo piyo", "Tweet (bird chirping)"),
          ("ゴロゴロ", "goro goro", "Purring (cat purr) / Rolling"),
      ]
      ]
  

  • print just the Korean list
  • Make a new list of lists, with the sub-lists having the transliteration, if it exists, if not then the words

Some problems adapted from PCC 5-11.

Summary

• You learned how to write conditional tests, which always evaluate to True or False
• You learned about some of the different ways that you can test
  ==, !=, >, <, element in list, …
• You learned to test with if - elif - else
• You learned to handle certain items in a list differently

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LAC: Language and the Computer Francis Bond.