Notebook 0: Python warm-up

Notebook 0: Python warm-up#

Use these short exercises to practise basic Python patterns before the data notebooks. Replace ... where shown, run the check, and change one example to see what happens.

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from pathlib import Path
import sys

# Find the repository from the notebook folder, solutions folder, or project root.
for _candidate in (Path.cwd().resolve(), *Path.cwd().resolve().parents):
    if (_candidate / "notebooks" / "workshop_checks.py").is_file():
        PROJECT_ROOT = _candidate
        break
else:
    raise FileNotFoundError(
        "Open this notebook inside the cloned workshop repository; "
        "notebooks/workshop_checks.py is required."
    )

sys.path.insert(0, str(PROJECT_ROOT / "notebooks"))

from workshop_checks import Check, run_checks

check = Check()

1: Predict the output#

What will this print? Choose A, B, or C before running the check.

numbers = [1, 2]
alias = numbers
alias.append(3)
len(numbers)

  • A: 2

  • B: 3

  • C: an error

answer_1 = ""  # replace with A, B, or C
Hint

Assignment gives two names to the same list. Appending through either name changes that list.

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run_checks("00_python_warmup_predict", locals())

2: Use variables and arithmetic#

Calculate the total cost for six items at seven units each.

price = 7
quantity = 6
total = ...
Hint

Multiply price by quantity.

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run_checks("00_python_warmup_arithmetic", locals())

3: Clean a string#

Remove surrounding whitespace and make the word lowercase.

word = "  PYTHON  "
clean_word = ...
Hint

Use the string methods .strip() and .lower().

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run_checks("00_python_warmup_string", locals())

4: Write a small function#

Complete is_even. It should return True for even numbers and False for odd numbers.

def is_even(number):
    ...
Hint

The remainder operator is %. An even number has remainder zero after division by two.

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run_checks("00_python_warmup_function", locals())

5: Build a list with a comprehension#

Create the squares of the numbers 1 through 4.

squares = [number ** 2 for number in ...]
Hint

Use range(1, 5).

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run_checks("00_python_warmup_list", locals())

6: Read a dictionary#

Select the value stored under the course key.

person = {"name": "Ada", "course": "Python"}
course = ...
Hint

Use square brackets with the key name.

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run_checks("00_python_warmup_dictionary", locals())