Values, Types, Variable Names, and Keywords

variable:

A name that refers to a value.

assignment:

A statement that assigns a value to a variable.

state diagram:

A graphical representation of a set of variables and the values they refer to.

keyword:

A reserved word that is used to parse a program; you cannot use keywords like if, def, and while as variable names.

operand:

One of the values on which an operator operates.

expression:

A combination of variables, operators, and values that represents a single result.

evaluate:

To simplify an expression by performing the operations in order to yield a single value.

statement:

A section of code that represents a command or action. So far, the statements we have seen are assignments and print statements.

execute:

To run a statement and do what it says.

interactive mode:

A way of using the Python interpreter by typing code at the prompt.

script mode:

A way of using the Python interpreter to read code from a script and run it.

script:

A program stored in a file.

order of operations:

Rules governing the order in which expressions involving multiple operators and operands are evaluated.

concatenate:

To join two operands end-to-end.

comment:

Information in a program that is meant for other programmers (or anyone reading the source code) and has no effect on the execution of the program.

syntax error:

An error in a program that makes it impossible to parse (and therefore impossible to interpret).

exception:

An error that is detected while the program is running.

semantics:

The meaning of a program.

semantic error:

An error in a program that makes it do something other than what the programmer intended.