checked the Moodle page for tomorrow’s lecture # My favorite equation \[
x=\frac{1}{2}x+5
\]
Exercise 2: Atomic types
2.1 In the code cell below, use the functions type() and print() to examine and print the types of the variables u, v, x, y, and z
# Assign five objects of different atomic types# to five different variables u, v, x, y, and zu =Nonev =Truex =10.2y =45z ="100.01"# Print the types of u, v, x, y, and z#print("u is of type ", type(u))#print("v is of type ", type(v))#...vartypes = {"u": u, "v": v, "x": x, "y": y, "z": z}for name, value in vartypes.items():print(f"{name} is of type ", type(value))
u is of type <class 'NoneType'>
v is of type <class 'bool'>
x is of type <class 'float'>
y is of type <class 'int'>
z is of type <class 'str'>
2.2 In the code cell below:
Cast the variable x defined in the code cell above to an integer and assign the resulting object to a new variable a. Then print the value and type of a
Cast the variable y defined in the code cell above to a string and assign the resulting object to a new variable b. Then print the value and type of b
Cast the variable y defined in the code cell above to a float and assign the resulting object to a new variable c. Then print the value and type of c
# Recast x, y, and z to three new variables a, b, and c.# Print the types and values of a, b, and ca =int(x)print("variable a has value ", a, " and type ", type(a))b =str(y)print("variable b has value ", b, " and type ", type(b))c =float(y)print("variable c has value ", c, " and type ", type(c))
variable a has value 10 and type <class 'int'>
variable b has value 45 and type <class 'str'>
variable c has value 45.0 and type <class 'float'>
Exercise 3: Operators
3.1 In the code cell below, use arithmetic operators to compute the following expressions. Then print the results:
\(1489 - 2078 + 1359\)
\(195 * 236 / 17\)
\(7.4^5\)
\((348 - 63)^4 / 72\)
# Compute the expressions and print the resultsprint("1: ", 1489-2078+1359)print("2: ", 195*236/17)print("3: ", 7.4**5)print("4: ", (348-63)**4/72)
3.2 In the code cell below, use augmentation operators to do the following:
Divide the variable x by 10 and overwrite it with the resulting value. Then print the value of x
Add the string ” Visualization” to the variable y and overwrite it with resulting value. Then print the value of y
Repeat the string variable z three times and overwrite it with the resulting value. Then print the value of z
# Assign three objects to three different variables x, y, and z.x =35y ="Data Science and"z ="Python"# Change and overwrite x, y, and z. Print the values of x, y, and zx /=10print("1: ", x)y +=" Visualization"print("2: ", y)z *=3print("3: ", z)
1: 3.5
2: Data Science and Visualization
3: PythonPythonPython
3.3 In the code cell below, use Boolean operators and the function len() to check if the following statements are true:
\(120 = 9 * 19 - 51\)
\(6 * 12 + 44 > 5^3\)
\((-3)^2 + 5 * -3 + 6 \geq 0\)
There are 28 or 32 letters including spaces in the phrase Data Science and Visualization
There are 17 letters including spaces in the phrase Boolean operatorsand\(20 < 3.5 * 4 + 3^2\)
# Check if the statements are trueprint("1: ", 120==9*19-51)print("2: ", 6*12+44>5**3, " (", 6*12+44, " < ", 5**3, ")")print("3: ", (-3)**2+5*-3+6>=0)phrase_len =len("Data Science and Visualization")print("4: ", (28|32) == phrase_len, " (length is ", phrase_len, ")")print("5: ", len("Boolean operators") and (20<3.5*4+3**2))
The the future value of an investment can be computed using the formula:
\[
A = P(1 + r)^t
\]
where \(A\) is the final amount, \(P\) is the initial amount, \(r\) is the annual interest rate, and \(t\) is the number of years. Do the following:
The initial amount is 10,000, the annual interest rate is 2.5%, and you save up for 6 years. Assign these values to three new variables P1, r1, and t1. Use the formula to compute the final amount. Assign the result to a new variable A1 and print the value.
The initial amount is 15,000, the annual interest rate is 4.25%, and you save up for 3 years. Assign these values to three new variables P2, r2, and t2. Use the formula to compute the final amount. Assign the result to a new variable A2 and print the value.
The initial amount is 2,500, the annual interest rate is 1.75%, and you save up for 12 years. Assign these values to three new variables P3, r3, and t3. Use the formula to compute the final amount. Assign the result to a new variable A3 and print the value.
Use the round() function to return the results with 2 decimal places. You will use the variables created in this excercise in the next exercise
# Compute and print accumulated savings under scenario 1P1 =10000r1 =2.5/100t1 =6A1 =round(P1*(1+r1)**t1, 2)print("A1 = ", A1)# Compute and print accumulated savings under scenario 2P2 =15000r2 =4.25/100t2 =3A2 =round(P2*(1+r2)**t2, 2)print("A2 = ", A2)# Compute and print accumulated savings under scenario 3P3 =2500r3 =1.75/100t3 =12A3 =round(P3*(1+r3)**t3, 2)print("A3 = ", A3)
A1 = 11596.93
A2 = 16994.93
A3 = 3078.6
Exercise 5: Containers
5.1 Use the code cell below to do the following:
Create a list with the names of the seven days of the week. Assign the list to the variable days
Use slice notation and the indexing operator on the list days to create two new lists weekdays, i.e., Monday through Friday, and weekend, i.e. Saturday and Sunday. Print the new lists
Use a list method to do add an extra Sunday to the end of the list weekend. Then print the list
Use a list method to remove the first occurence of the Sunday from the list weekend. Now print the list again
Use a list method to reverse the order of the list weekdays so the first element is now Friday. Then print the list again
# Create a list the names of the days of the weekdays = ["Monday", "Tuesday", "Wednesday", "Thursday", "Friday","Saturday", "Sunday"]# Create two list with weekdays and weekendweekdays = days[0:5]print("1: week days: ", weekdays)weekend = days[-2:7]print("2: weekend: ", weekend)# Add "Sunday" to the end of the list weekendweekend.append("Sunday")print("3: extended weekend: ", weekend)# Remove the first occurence of "Sunday" from the list weekendweekend.pop(1)print("4: reduced extended weekend: ", weekend)# Reverse of the order of the list weekdaysweekdays.reverse()print("5: week days reversed: ", weekdays)
Create a dictionary that maps the keys Initial amount, Interest rate, Years, and Final amount to the values stored in the variables P1, r1, t1, and A1 that you created under the first scenario in exercise 4. Assign the dictionary to the new variable S1.
Create corresponding dictionaries for the second and third scenarios in exercise 4 and assign them to the new variables S2 and S3
Now create a nested dicitionary that maps the keys Scenario 1, Scenario 2, and Scenario 3 to the dictionaries stored in the variables S1, S2, and S3. Assign the nested dictionary to the variable accumulated_savings
Use the indexing operator on the nested dictionary accumulated_savings to access the final amount under scenario 2 and print it
# Create a dictionary for the first scenario in exercise 4S1 = {"Initial amount": P1,"Interest rate": r1,"Years": t1,"Final amount": A1,}# Create corresponding dictionaries# for the second and third scenarios in exercise 4S2 = {"Initial amount": P2,"Interest rate": r2,"Years": t2,"Final amount": A2,}S3 = {"Initial amount": P3,"Interest rate": r3,"Years": t3,"Final amount": A3,}# Create a nested dictionary# of accumulated savings under the three scenariosaccumulated_savings = {"Scenario 1": S1,"Scenario 2": S2,"Scenario 3": S3,}# Access the final amount under scenario 2 and print itprint("4: final amount under scenario 2: ", accumulated_savings["Scenario 2"]["Final amount"])
4: final amount under scenario 2: 16994.93
Exercise 6: String methods
Use the code cell below to do following:
Go to the FUTUREDEMICS page on Roskilde University’s research portal. Copy the URL and assign it to a new variable URL
Use a string method to count the number forslashes / in the URL
Use the functions len() and set() to count how many different unique characters the URL contains
Use a string method and the indexing operator to split URL into two new strings: One containing the base URL up to and inclduing .dk and one containing the part of the URL after the second to last forslash, i.e., the title of the research project. Assign the new strings to the variables base_URL and project_title
Use a string method to replace all hyphens - in project_title with whitespaces
Use a string method to strip the string ” futuredemics” from project_title
Use a string method to put project_title in titlecase. Then print it
# Assign the FUTUREDEMICS URL to a new variable URLURL ="https://forskning.ruc.dk/"\+"da/projects/"\+"nordic-pandemic-preparedness-modelling-network-futuredemics/"# Count the number of forslashes in URL#print("2: slashes: ", URL.count("/"))# Count the number of unique characters in URL#print("3: unique chars: ", len(set(URL)))# Create two new string variables from URLURL_parts = URL.partition(".dk")base_URL ="".join(URL_parts[0:2])project_title = URL_parts[2].split("/")[-2]#print(f"4: base URL: {base_URL}\n project title: {project_title}")# Replace hyphens with whitespace in project_titleproject_title = project_title.replace("-", " ")#print("5: project title, spaced: ", project_title)# Strip the word "futuredemics" from the project tilteproject_title = project_title.removesuffix(" futuredemics")#print("6: project title, shortened: ", project_title)# Title case project_titleproject_title = project_title.title()# Print the project titleprint(project_title)
Nordic Pandemic Preparedness Modelling Network
Exercise 7: Exporting Jupyter Notebooks to PDF
Several possibilities for exporting Jupyter Notebooks to PDF exists. Two of them are:
Print to PDF via HTML:
Select File > Save and Export Notebook As > HTML in Jupyter Notebook. An HTML file is saved in you Downloads folder.
Open the HTML, press Ctrl + P, select Print to PDF, and choose a file path
Run pip install nbconvert in a code cell in Jupyter Notebook
Select Kernel > Restart Kernel in Jupyter Notebook
Export to PDF: Select File > Save and Export Notebook As > PDF in Jupyter Notebook. An PDF file is saved in you Downloads folder. Open it, click save, and choose a file path
The advantage of the first approach is that it has no dependencies, i.e., you do not have to install other applications to make it work. The drawback of the first approach is that you have limitied control over the output. For example, lines in code cell that are too long to fit the page are cut off rather than shown across several lines. To make the second approach work, you have to install the dependencies listed. Once you have done that, it is fast and easy to convert to PDF via LaTeX. If following the steps listed here does not enable you to produce a PDF via LaTeX (if you use Mac or Linux you may run into trouble), I recommend that you use your favorite search engine or go talk to a large language model to find a solution that works on your system.
Try exporting your notebook to PDF using both methods. You will need to export a Jupyter Notebook to PDF when you will eventually submit your exam mini-project on May 1.
