Keep the useful bits, human.
Beginner field notes
- A source-code editor saves plain text. A word processor’s formatted document is a different kind of file.
- Syntax colors help you read recognizable code. Coloring a line is not the same as executing it.
- Saving writes edits to the source file. Starting the language tool to run that file is a separate action.
See a worked example
Save the first source file
One reviewed sample, shared across levels. Nothing here runs on your computer.
Example review recorded 2026-10-07 · version 1.
print("Hello, human!")A plain-text file named hello.py contains the line above.
No program output is produced just by saving it.The output box describes the result of saving, not the result of Python execution. Save in your own experiment folder; do not overwrite an unrelated file.
Sources for this sampleVisual
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flowchart LR
E["Edit text in editor"] -->|"Save"| F["hello.py on disk"]
F --> N["Not executed yet"]Full explanation and primary sources
Reviewed explanation
A text editor changes the text stored in a file. A code editor adds features such as syntax highlighting, which colors recognizable parts of code. For source files, use an editor that saves plain text rather than a word processor’s formatted document. Styling in the editor is not itself part of the program.
To prepare the example, create a new plain-text file in your human-lab folder and save it as hello.py. Check the complete filename: some file managers hide extensions, so a file displayed as hello.py could actually have an extra .txt extension. The .py name tells you the intended source language; it does not install Python or execute the file.
Editing changes the text you see in the editor. Saving writes those changes to the file. Running the saved file is another action. If a program seems to ignore a change, confirm that you saved the correct file before investigating more complicated causes.
Source collection
- MDN: Code editors
Used in: Quick notes · Worked example · Lesson text
Plain-text source editing, syntax highlighting, opening source files and editor language features.
Plain-text source editors versus formatted document editors, and syntax-highlighting features.
- Visual Studio Code: Basic editing
Used in: Quick notes
Unsaved buffers, explicit and automatic saves, Hot Exit, format-on-save, indentation detection, encoding selection and comparison with saved files.
- Python 3.13: Command line and environment
Used in: Quick notes
Script and module execution, whole-input parsing, script arguments, import-path initialization, -I, -P, -u and -v options.
- MDN: Dealing with files
Used in: Worked example · Lesson text
Filename/extension handling and making extensions visible while organizing project files.
Notes AI source review · 2026-10-17
AI source comparison recorded 2026-10-07. Human learner validation is pending.
Quick quiz · one question
Diagnose an unsaved change
Sample scenario. Synthetic plain-text editor with autosave and save hooks off. Each Run reads the saved hello.py from disk using an available Python 3 interpreter. Both versions contain only the displayed print call. This browser does not run Python or write files.
- Initially saved in hello.py
print("Hello, human!")- Unsaved editor buffer
print("Hello, robot!")- Step 1
Run the saved hello.py file with Python 3- Step 2
Save the editor buffer to hello.py- Step 3
Run the saved hello.py file with Python 3
The editor shows an unsaved change. Follow Run, Save, Run. Which greeting remains saved, and which two greeting lines appear in order?
Why this answer?
Answers stay on this device.
Sources and exercise scope
- MDN: Code editors
Plain-text code editing and saving; editor features are separate from the text of a program.
- Python 3.13: Using the Python Interpreter
Interpreter command discovery depends on the installation; a supplied filename identifies the script read by the interpreter.
- Python 3.13: An Informal Introduction to Python
print displays a string without its enclosing source quotation marks; interactive prompts are distinct from entered source.
Original synthetic exercise. AI comparison against primary documentation recorded on 2026-10-08; the references above state their scope. Human learner validation has not been run. A result here records this attempt; it does not establish mastery.
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