Date arithmetic (Timedelta) in Data Analysis Python - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

Calculate the difference in days between two dates

What is the output of this code snippet that calculates the difference in days between two dates?

Data Analysis Python

import pandas as pd
start_date = pd.to_datetime('2024-01-01')
end_date = pd.to_datetime('2024-01-15')
diff = end_date - start_date
print(diff.days)

A 15

B 14

C 13

D Error

💡 Hint

Remember that the difference between dates counts full days between them.

The difference between January 15 and January 1 is 14 full days, so diff.days returns 14.

❓ data_output

intermediate

Add a timedelta to a date

What is the resulting date after adding 10 days to '2024-03-10'?

Data Analysis Python

import pandas as pd
initial_date = pd.to_datetime('2024-03-10')
new_date = initial_date + pd.Timedelta(days=10)
print(new_date.strftime('%Y-%m-%d'))

A 2024-03-20

B 2024-03-10

C 2024-03-21

D 2024-03-19

💡 Hint

Adding 10 days means moving forward 10 calendar days.

Adding 10 days to March 10 results in March 20, 2024.

❓ visualization

advanced

Plotting date ranges with timedelta

Which option correctly creates a plot showing dates from '2024-01-01' to '2024-01-10' with daily intervals?

Data Analysis Python

import pandas as pd
import matplotlib.pyplot as plt
dates = pd.date_range(start='2024-01-01', end='2024-01-10')
values = range(len(dates))
plt.plot(dates, values)
plt.xlabel('Date')
plt.ylabel('Value')
plt.title('Date Range Plot')
plt.show()

A A scatter plot with dates missing Jan 5

B A bar plot with dates on y-axis and values on x-axis

C A line plot with dates on x-axis from Jan 1 to Jan 10 and values 0 to 9 on y-axis

D An empty plot with no data

💡 Hint

Check if the dates cover the full range and if the plot type matches the code.

The code creates a line plot with dates from Jan 1 to Jan 10 on the x-axis and values 0 to 9 on the y-axis.

🧠 Conceptual

advanced

Understanding timedelta components

Given a timedelta of 3 days, 4 hours, and 30 minutes, what is the total number of seconds?

Data Analysis Python

from datetime import timedelta
td = timedelta(days=3, hours=4, minutes=30)
total_seconds = td.total_seconds()
print(int(total_seconds))

A 275400

B 259200

C 302400

D 273000

💡 Hint

Calculate seconds for days, hours, and minutes separately then add.

3 days = 259200 seconds, 4 hours = 14400 seconds, 30 minutes = 1800 seconds; total = 259200 + 14400 + 1800 = 275400 seconds.

🔧 Debug

expert

Identify the error in timedelta subtraction

What error does this code raise when subtracting a timedelta from a string date?

Data Analysis Python

from datetime import timedelta
start = '2024-05-01'
result = start - timedelta(days=5)
print(result)

A AttributeError: 'str' object has no attribute 'days'

B ValueError: invalid literal for int() with base 10

C No error, prints '2024-04-26'

D TypeError: unsupported operand type(s) for -: 'str' and 'datetime.timedelta'

💡 Hint

Check the data types involved in the subtraction.

You cannot subtract a timedelta directly from a string; the string must be converted to a date first.