2.3: Expressions and statements
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An expression is a combination of values, variables, and operators. A value all by itself is considered an expression, and so is a variable, so the following are all legal expressions:
>>> 42 42 >>> n 17 >>> n + 25 42
When you type an expression at the prompt, the interpreter evaluates it, which means that it finds the value of the expression. In this example,
n has the value
n + 25 has the value
A statement is a unit of code that has an effect, like creating a variable or displaying a value.
>>> n = 17 >>> print(n)
The first line is an assignment statement that gives a value to
n. The second line is a print statement that displays the value of
When you type a statement, the interpreter executes it, which means that it does whatever the statement says. In general, statements don’t have values.