By the end of this lesson
Trace simple assignments and produce a greeting using a named value.
Before you start
- Python 3.12 or a compatible newer Python 3 interpreter; no external packages.
- Complete lesson 1 in this route, or be comfortable with its examples.
Three words to know
- Variable
- A name referring to a value.
- Assignment
- Using = to bind a name to a value.
- Comment
- A note after # that Python does not execute.
1. Read from top to bottom
A small script normally runs one statement after another. An assignment binds a name; it does not print anything. Descriptive names make later changes easier: learner_name tells the reader more than x. Names are case-sensitive, so learner and Learner are different.
learner_name = "Sam"
lesson_count = 22
print(learner_name)
print(lesson_count)
What you should see · example output
Sam 22
2. Reassignment uses the current value
The right-hand side is evaluated first. Then the name on the left refers to that result. Reassigning one name does not automatically update another name that previously received its old integer value.
completed = 2
previous = completed
completed = completed + 1
print(previous)
print(completed)
What you should see · example output
2 3
3. Make intent visible
Use lower_case_with_underscores for ordinary variable names. Do not name a variable print, list or input: doing so hides a useful built-in. Comments should explain a decision rather than repeat every character of a statement.
# Keep this example independent of the machine clock.
practice_day = "Monday"
print(f"Practice on {practice_day}")
What you should see · example output
Practice on Monday
YOUR TURN
A small check before you continue
Set completed to 4, add 2 to it and print the result. Predict previous if it was assigned completed before the addition.
Show a suggested answer
The result is 6. previous remains 4 when assigned before the addition. Assignment copied the reference to the earlier integer; it did not create a live formula.
Sources and scope
Documentation and examples reviewed 2026-10-18. Provider screens, package versions and output wording can differ. Examples show expected outcomes; they are not a claim that OpenViST connected to your server or verified your setup.