61 lines
1.5 KiB
Python
61 lines
1.5 KiB
Python
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# Lesson 02: Variables
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#
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# A variable is a named container that holds a value. Think of it like a
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# labeled box: you put something inside and can retrieve it later by name.
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#
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# To run this file:
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# python 02_variables.py
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# --- Creating variables ---
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# Use the '=' sign to assign a value to a variable name.
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name = "Alice"
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age = 30
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height = 5.6
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is_student = True
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print(name)
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print(age)
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print(height)
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print(is_student)
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# --- Using variables in print ---
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print("Name:", name)
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print("Age:", age)
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# --- Updating variables ---
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# You can change the value stored in a variable at any time.
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age = 31
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print("Next year, age:", age)
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# --- Variable naming rules ---
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# Good names: descriptive, lowercase, underscores between words
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first_name = "Bob"
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last_name = "Smith"
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total_score = 100
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# Bad (but technically valid) names — avoid these:
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# x = "Bob" too vague
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# FirstName = "Bob" use lowercase_underscore style for variables
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# --- Combining variables (string formatting) ---
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# f-strings let you embed variables directly inside a string.
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# Put an 'f' before the opening quote, then use {variable_name} inside.
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greeting = f"Hello, my name is {first_name} {last_name}."
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print(greeting)
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score_message = f"Total score: {total_score}"
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print(score_message)
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# --- Multiple assignment ---
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# You can assign the same value to several variables at once.
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x = y = z = 0
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print(x, y, z)
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# Or assign different values on one line.
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a, b, c = 1, 2, 3
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print(a, b, c)
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# --- Try it yourself ---
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# Create variables for your own name, age, and favorite number.
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# Print a sentence that uses all three.
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