Section 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):
If you type an expression in interactive mode, the interpreter evaluates it and displays the result:
But in a script, an expression all by itself doesn't do anything! This is a common source of confusion for beginners.
Type the following statements in the Python interpreter to see what they do:
Checkpoint 2.6.1.
csp-10-2-2: Which of the following is an expression?
5
An expression is a combination of values, variables, and operators.
x = 5
An expression is a combination of values, variables, and operators.
x + 1
An expression is a combination of values, variables, and operators.
all of the above
All of the above are correct! An expression is a combination of values, variables, and operators.
none of the above
An expression is a combination of values, variables, and operators.
Checkpoint 2.6.2.
Click on the expression(s) that will **not** return a value when typed in an interpreter.
Try typing these expressions in a python interpreter to see what they do.
12:
x = 73:
x + 12:
x += 52:#using += is the same as writing out x = x + 52:
