DynamicVibePython learning
How to study · reference & help

One lesson at a time

Read the idea, then follow the named exercise steps. On a phone, use Idea, Code and Output to switch views. Review days begin with recall before the rebuild. A self-review mark is not a scored answer.

Run, inspect, repair

Run loads Python in your browser on the first use, so you need an internet connection. Read Output and the check result. Stop interrupts a run; it keeps your code. Reset restores the selected starter, replacing that exercise’s draft. Use an authored hint before asking for help.

Keep your work

Code drafts, progress and Notes save on this device when browser storage is available. They do not sync through your login. Use Backup & records above to download saved learning records, preview an import or undo the latest import. Copy unsaved text first; clearing browser data can remove local work. A save warning means you should copy your work before leaving.

Practice files and reports

Each browser Run starts in a fresh temporary workspace. A sample file exists only when that run’s code creates it; these are not your computer’s files. On report tasks, use Preview to inspect the actual text and Download to request a copy before another Run, Reset, exercise change or leaving. Reports do not save through tutor login. Read files and write reports.

Get tutoring when you need it

Lessons and checkpoints do not need tutor login. Unlock the tutor through Training’s shared tutor access, then use its return link to come back here. Your question is only sent when you press Send. Do not paste passwords or private production data.

Python words in plain language

Assignment and type
frames = 96 binds a name to an integer. "96" is text, not the same numeric value. Values and names.
List and index
A list keeps items in order. Positions start at zero; the final nonnegative index is length minus one. List lookups.
Loop and indentation
A for loop processes each item. Indentation groups its repeated statements; a statement outside the block runs separately. Loops.
Parameter, argument and Return
A parameter names an input in a definition; an argument supplies its value in a call. Return gives a result to the caller; print displays it. A function that only prints returns None. Functions.
Dictionary and schema
A dictionary labels values with keys. A schema states the required fields and types; a missing fact is not automatically zero. Dictionaries · Validation.
File, CSV and JSONL
A file stores bytes/text. CSV needs a quoting-aware parser; JSONL contains one JSON value per line. Browser practice files are temporary, not computer files. CSV · JSONL.
Denominator and evidence
A rate divides a count by its declared eligible total. Keep exclusions visible. A quiz score, practical check and self-review are different evidence. Quality rates.

Read the error, then make one repair

SyntaxError / IndentationError
Python could not parse the code. Inspect the named line and the preceding line for a missing colon, unmatched quote/bracket or inconsistent indentation. Review blocks.
NameError
A name has no value here. Compare case and spelling, and check that assignment happens before use. Do not replace an unknown parameter with a fixed sample.
TypeError / ValueError
A wrong kind of value or an unacceptable value can fail an operation. Inspect the supplied input and declared policy; do not broadly suppress the error. Narrow error handling.
IndexError / KeyError
The requested position or key is missing. Inspect the collection and interface instead of guessing a fallback. Indices · Keys.
Run stays loading / runtime or checker unavailable
This is not proof that your answer is wrong. Stop if available, copy your draft, check your connection and retry. If it repeats, keep the visible error and use the readable lesson/hints. Never reset or clear browser storage as the first repair.
Expected sample prints, but a check fails
Read the named contract and test changed/empty inputs. The helper may return None, use a fixed value or stop too early even when the sample looks right. A failed check is not a request to copy the expected output.

Press Escape while working inside this panel to close it and return focus to its summary. Without JavaScript, use the summary again. For local Studio commands, use terminal troubleshooting.

← Route Week 4 · Day 17 of 40

Writing files

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Lesson idea Tap to fold
Recall

Which file mode means read?

Show the answer

"r".

Today

Write, close and verify a report

Writing is a side effect: it changes a file. A print on screen does not prove a report was saved. Close the write block, reopen the file and inspect its contents.

w replaces a report; a appends. Use w for the first write and a only when deliberately adding more text. Explicit UTF-8 keeps names portable between systems. Browser reports are temporary; use Download to request a computer copy before leaving or running again.

# Write, close and verify a report.
with open("report.txt", "w", encoding="utf-8") as file:
    file.write("Museum · review\n")

with open("report.txt", "a", encoding="utf-8") as file:
    file.write("Canal · approved\n")

with open("report.txt", encoding="utf-8") as file:
    print(file.read(), end="")

The saved report contains both rows, each ending with a newline. end="" prevents print from adding a second final newline.

Inspect the report preview and download it if useful. A download request is not a course pass or confirmation that your browser saved the file.

Predict, explain, then verify

These brief checks are self-reviewed, not quiz scores. Browser runs use fresh temporary files; they do not open your computer’s files. Download useful reports before another Run, Reset, exercise change or leaving.

Choose a mode

A second w block opens the same report. What happens to the first block’s text?

Compare your answer · self-reviewed

It is replaced. Use a for an intentional append, and read back the result.

Separate evidence

Does printing a correct line prove the file contains that line?

Compare your answer · self-reviewed

No. Verify the saved file itself by reopening it.

Keep a copy

How does the browser report become a file you can keep?

Compare your answer · self-reviewed

Choose Download. The page requests a download but cannot confirm your browser saved it.

Now

Choose an exercise to load its prompt.

day-17.py standard Python · runs in this browser
Output

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