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Engineering LibreTexts

2.6: Expressions

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 (assuming that the variable x has been assigned a value):

 

17
x
x + 17

If you type an expression in interactive mode, the interpreter evaluates it and displays the result:

>>> 1 + 1
2

But in a script, an expression all by itself doesn't do anything! This is a common source of confusion for beginners.

Exercise 1: Type the following statements in the Python interpreter to see what they do:

5
x = 5
x + 1