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Engineering LibreTexts

2.6: Expressions

  • Page ID
    2994
  • [ "article:topic", "authorname:severancec", "python (language)", "license:ccbyncsa" ]

    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