Python for Everyone, ch 1-5
semantic error
An error in a program that makes it do something other than what the programmer intended.
bug
An error in a program.
boolean expression (T/F)
An expression whose value is either True or False.
print statement
An instruction that causes the Python interpreter to display a value on the screen.
% modulus operator
An operator, denoted with a percent sign (%), that works on integers and yields the remainder when one number is divided by another.
#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.
branch
One of the alternative sequences of statements in a conditional statement.
value
One of the basic units of data, like a number or string, that a program manipulates. (on the right side of the statement)
logical operator (and, or, not)
One of the operators that combines boolean expressions: and, or, and not.
comparison operator
One of the operators that compares its operands: ==, !=, >, <, >=, and <=.
operand
One of the values on which an operator operates.
secondary memory
Stores programs and data and retains its information even when the power is turned off. Generally slower than main memory. Examples of secondary memory include disk drives and flash memory in USB sticks.
main memory
Stores programs and data. Main memory loses its information when the power is turned off.
condition
The boolean expression in a conditional statement that determines which branch is executed.
central processing unit
The heart of any computer. It is what runs the software that we write; also called "CPU" or "the processor".
machine code
The lowest-level language for software, which is the language that is directly executed by the central processing unit (CPU).
semantics
The meaning of a program.
5/2 = 2, floor division
The operation that divides two numbers and chops off the fractional part.
problem solving
The process of formulating a problem, finding a solution, and expressing the solution.
body
The sequence of statements within a compound statement.
rules of precedence
The set of rules governing the order in which expressions involving multiple operators and operands are evaluated. PEMDAS ex/ cost = meal + meal * tax
parse
To examine a program and analyze the syntactic structure.
interpret
To execute a program in a high-level language by translating it one line at a time.
concatenate
To join two operands end to end.
evaluate
To simplify an expression by performing the operations in order to yield a single value.
compile
To translate a program written in a high-level language into a low-level language all at once, in preparation for later execution.
short circuit
When Python is part-way through evaluating a logical expression and stops the evaluation because Python knows the final value for the expression without needing to evaluate the rest of the expression.
prompt
When a program displays a message and pauses for the user to type some input to the program.
guardian pattern
Where we construct a logical expression with additional comparisons to take advantage of the short-circuit behavior. ex/ y != 0
traceback
A list of the functions that are executing, printed when an exception occurs.
mnemonic
A memory aid. We often give variables mnemonic names to help us remember what is stored in the variable. ex/ hours instead of njddbf3
variable
A name that refers to a value. (on the left side of statement)
source code
A program in a high-level language.
high-level language
A programming language like Python that is designed to be easy for humans to read and write.
low-level language
A programming language that is designed to be easy for a computer to execute; also called "machine code" or "assembly language".
portability
A property of a program that can run on more than one kind of computer.
keyword
A reserved word that is used by the compiler to parse a program; you cannot use keywords like if, def, and while as variable names. (print, elif, etc)
statement
A section of code that represents a command or action. So far, the statements we have seen are assignments and print statements.
program
A set of instructions that specifies a computation.
operator
A special symbol that represents a simple computation like addition, multiplication, or string concatenation. (+, -, ...)
= assignment
A statement that assigns a value to a variable.
compound statement
A statement that consists of a header and a body. The header ends with a colon (:). The body is indented relative to the header.
conditional statement
A statement that controls the flow of execution depending on some condition.
float(), 1.0, floating point
A type that represents numbers with fractional parts.
string
A type that represents sequences of characters.
1, integer
A type that represents whole numbers.
interactive mode
A way of using the Python interpreter by typing commands and expressions at the prompt.
type
A category of values. The types we have seen so far are integers (type int), floating-point numbers (type float), and strings (type str).
expression
A combination of variables, operators, and values that represents a single result value.
nested conditional
A conditional statement that appears in one of the branches of another conditional statement.
chained conditional
A conditional statement with a series of alternative branches. (alternative sequences)
