Colab

basic values and types

  1. calculate 2+8 and put the result in tha variable x.
    • print the value of x

      hint: use the function print()

    • what is the type of x?

      hint: use the function type()

  2. calculate 5 / 2 and put the result in the variable y. print y and the type of y
  3. put "hello world" into a variable named greeting.
    • print the variable and the type of the variable
    • what is the len of greeting?

      hint: use the function len()

  4. put the values 1, 2 and 3 into list1 and the values "a", "b" and "c" into list2.
    • calcluate list1 + list2 and put the result into list3
    • print list3
    • print the type of list3
    • print the len of list3

getting help

suppose we want to understand how to use a function. we can use the help() function for that!

  1. let’s try to use the function str.upper(), by copying this code below and running it: 
    print( "hello".upper() )
  2. lets see how to get help for a function. type the following code into a cell below. this will explain what the function str.upper does 
    help("hello".upper)

some simple string functions

  1. lets get help for all the cool functions the type str has. lets call help(str). run the following code: 
    help(str)

  2. read the documentation you’ve just printed, for the following functions: lower, upper, title, islower, isupper and try to figure out what they do. you can try to use them, read the documentation again, google for them. anything that helps you understand.

  3. convert this string to uppercase "the quick brown fox jumped over the lazy dog"

    hint: use one of the functions you’ve learned in question #2

  4. is the string "I JusT mEt YoU, anD tHIs is CraaZy, sO CAll mE mayBe" in lower case? can you convert it to lower case?

    hints :

    1. there is a function that checks if a string is lower case
    2. there is a function that converts a string to lower case

input from the user

run the following code to get input from the user (you are the user!)

name = input("what is your name: ")
print("hi", name)

your programs now have the power to ask questions!

BMI: Body mass index

In health the BMI (body mass index) is defined as \(BMI=\frac{weight}{height^2}\)

where the weight is in kilograms, and the height is in meters.

for example for weight 80kg and height 2.0m the BMI is $80 / (2^2) = 80 /4 = 20 $

  1. put 97 into a variable called weight
  2. put 1.84 into a variabled called height
  3. write code to compute and print the bmi

BMI with input from user

  1. use the input() function to ask the user for his weight, put in variable weight
  2. what is the type of the variable weight?
  3. use the following code to convert the value to a float 
    w = float(weight)

    what is the type of w now?

  4. ask the user for his height and convert to float
  5. compute and print the bmi

help for str.split() function

print the help for the function str.split

hint: use the help() function

split a string

  1. create the following string, and put it in a variable called sent 
    "the quick brown fox jumped over the lazy dog"

  2. then split it into a list so that each word is an an element in the list.
    and put the result into another variable called words

  3. print the variable words

expected ouput:

['the', 'quick', 'brown', 'fox', 'jumped', 'over', 'the', 'lazy', 'dog']

str.join()

  1. use the function help to read the documentation for the str.join function
  2. read this code 
    mylist = ["one", "two", "three"]
result = " ".join(mylist)
print(result)
    1. can you guess what this code does ?
    2. what is the function join?
    3. use help or documentation online if you can’t guess
    4. copy this code to the cell below and run it to see if you were right

using str.upper() and str.join()

  1. split the sentence "the quick brown fox jumped over the lazy dog" into words using the function .split() and put the result in a variable called words .

  2. replace the the words “dog” and “fox” in the words list with uppercase “DOG” and “FOX”

    HINTS:

    • use the .upper() function
    • use indexing like words[3] to acccess a particular word in the words list

  3. use the function join to convert the list back into a string

  4. print the result

expected output:

"the quick brown FOX jumped over the lazy DOG"

4 boom

in this exercise, we’re going to take some song lyrics, and replace every 4th word of each line with the word “boom”. and then print out the lyrics.

NOTE: this exercise is simple but takes a lot of lines of code. we will learn loops IN THE NEXT LESSON. loops will help us write shorter solutions, but for now YOU DONT NEED LOOPS

use the following code, which puts an important 😜 string in a variable named song

song = """
Never gonna give you up
Never gonna let you down
Never gonna run around and desert you
Never gonna make you cry
Never gonna say good bye
Never gonna tell a lie and hurt you
"""

This is important

  1. split this string into a list of lines. put it in variable called lines

    hint: string have a function called .splitlines()

  2. split the line 0 into words. put it in variable called words0
    • now also split line 1. put it into words1
    • repeat for line 2 …, line 5, put each into word1, … word5

    hint: this should take you 6 simples lines.

  3. replace the 4th word of line 1, line 2, … line 6 with the word "boom"`

    hint: you don’t need loops. this again takes 6 lines

  4. now join words0. put the result into variable boom0
    • continue to join words1, words2 … words5 into boom1, boom2 … boom5

  5. create a list that contains boom0, boom1, … boom5, call it boom

  6. join the lines in boom back into a string. put it into a variable called result

    hint: use this code

    result = "\n".join(boom)
  7. print the result

This is important

expected output:

Never gonna give you boom
Never gonna let you boom
Never gonna run around boom desert you
Never gonna make you boom
Never gonna say good boom
Never gonna tell a boom and hurt you

### useful: data
song = """Never gonna give you up
Never gonna let you down
Never gonna run around and desert you
Never gonna make you cry
Never gonna say good bye
Never gonna tell a lie and hurt you
"""

Dictionary

  1. create a dictionary that maps the name of cheeses to prices of 100mg of that cheese.

     gouda costs 4.99 
 Edam costs 2.45
 Camambert costs 7.75
 Bree costs 7.27
  2. without using “head math”, write simple code to compute the costs of gouda, edam and camambert together

    hint: the solution is one simple but long line of code, which uses the + operator 3 times

  3. add a new cheese to the dictionary: Cottage cheese, which costs 3.2

    hint: the solution takes just one very simple line of code

  4. the government has added a new tax on milk products, now every cheese costs has increased by 27% ! can you update the costs in the dictionary?

    hint: the solution takes 5 (almost identical) lines of code

  5. can you use the round() function to round the prices of cheese, so that it has costs in dollars and cents (Shekels and agorot)?

    hint: what does the following code do?

     pi = 3.14159265
 print(pi)
 pi_rounded = round(pi, 2)
 print(pi_rounded)

len and indexing

quote = "everything should be as simple as possible, but not simpler. Albert Einstein"
  1. write code to check how many letters/characters are in this qoute.

    hint: use the function len()

  2. split this qoute into words. how many words are in this quote?

  3. write code to print:
    1. the 1st letter in the quote
    2. the 7th word
    3. the 1st letter of the 7th word
    4. the last letter in the quote
    5. the last letter of the 9th word

hint: the function len() is useful to figuring out what is the last letter/word

len, indexing and input

  1. what would the following code print? first try to answer yourself, then copy the code and run it to see if you guessed right
hi = "hello "
greeting = hi * 3
print(greeting)

  1. use the input() function to ask the user for full name.

  2. print the length of the name

  3. print the last letter of the name 100 times