Ch 2 Simple Python Data Flashcards
assignment token
= is Python’s assignment token, which should not be confused with the mathematical comparison operator using the same symbol
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
data type
a set of values. the type of a value determines how it can be used in expressions. so far, the types you have seen are integers (int), floating-point number (float), and strings (str)
decrement
decrease by 1
evaluate
to simplify an expression by performing the operations in order to yield a single value
expression
a combination of operators and operands (variables and values) that represents a single result value. Expressions are evaluated to give that result.
float
A Python data type which store floating-point numbers. Floating-point numbers are stored internally in two parts: a base and an exponent. When printed in the standard format, they look like decimal numbers. Beware of rounding errors when you sue floats and remember that they are only approximate values.
increment
Both as a noun and as a verb, increment means to increase by 1
initialization (of a variable)
To initialize a variable is to give it an initial value. Since in Python variables don’t exist until they are assigned values, they are initialized when they are created. In other programming languages this is not the case, and variables can be created without being initialized, in which case they have either default or garbage values
int
a Python data type that holds positive and negative whole numbers.
integer division
An operation that divides one integer by another and yields an integer. Integer division yields only the whole number of times that the numerator is divisible by the denominator and discards any remainder.
keyword
A reserved word that is used by the compiler to parse program; you cannot use keywords ( like if, def, and while) as variable names
modus operator
Also called remainder operator or integer operator. Gives the remainder after performing integer division
object
Also known as a data object (or data value). The fundamental things that programs are designed to manipulate (or that programmers ask to do things for them).
operand
One of the values on which an operator operates.
operator
A special symbol that represents a simple computation like addition, multiplication, or string concatenation.
prompt string
Used during interactive input to provide the user with hints as to what type of value to enter.
reference diagram
A picture showing a variable with an arrow pointing to the value (object) that the variable refers to. See also state snapshot.
rules of precedence
the set of rules governing the order in which expressions involving multiple operators and operands are evaluated. PEMDAS. 1 parentheses, 2 exponentiation, 3 multiplication and division, 4 additions and subtraction. Those operators that share a level (like multiplication and division) execute from left to right. So 6 * 9 / 7 would execute as (6 * 9) / 7. Exponentiation is read from right to left. So 4 ** 2 ** 3 would be 2 ** 3 and then 4 ** 8.
state snapshot
A graphical representation of a set of variables and the values to which they refer, taken at a particular instant during the program’s execution.
statement
An instruction that the Python interpreter can execute. So far we have only seen the assignment statement, but we will soon meet the import statement and the for statement, i.e., a statement is anything and everything that makes up one line of Python code
str
A Python data type that holds a string of characters.
type conversion function
A function that can convert a data value from one type to another
value
A number or string (or other things to be named later) that can be stored in a variable or computed in an expression.
variable
A name that refers to a value
variable name
A name given to a variable.
