Python Chapter 2
A comment in Python is denoted by the ____ character.
#
This symbol marks the beginning of a comment in Python
#
modulus operator
% performs division but instead of returning the quotient, it returns the remainder.
Remainder operator
%, Divides one number by another and gives the remainder
This is an operator that raises a number to a power.
**
_________ is a Python math operator which raises a number to a power
**
Exponent operator
**, Raises a number to a power
Multiplication operator
*, multiplies one number by another
Addition Operator
+ Adds two numbers
Subtraction operator
-, subtracts one number from another
Division operator
/, Divides one number by another and gives the result as a floating-point number
This operator performs integer division
//
Integer division operator
//, Divides one number by another and gives the result as an integer
In Python, the value of 9 % 2 =
1
In Python, the value of 12 / 2 - 4 =
2.0
In Python, the value of 14 / (11 - 4) =
2.0
In Python, the value of 6 + 3 * 5 =
21
In Python, the value of (6 + 2) * 3 =
24
In Python, the value of 9 + 14 * 2 - 6 =
31
Variable names which would be illegal in Python
3dGraph, Mixture#3
In Python, the value of 9 // 2 =
4
In Python, the value of 9 + 12 * (8 - 3) =
69
software requirement
A single task that a program must preform in order to satisfy the customer
exception
An error that occurs while a program is running, causing the program to halt if the error is not properly dealt with.
mixed-type expression
An expression that contains operands of different data types; also called mixed mode expression
Operator Precedence
Exponentiation **; Multiplication, division, and remainder * - / - // - %; Addition and subtraction + -
/* is a character used for writing comments in Python
False
Variable names can have space
False
// operator
When the result is positive, it is truncated, which means that its fractional part is thrown away. When the result is negative, it is rounded away from zero to the nearest integer
The five stages of the Program Development Cycle are: Design the program, ___________, Correct Syntax Errors, _____________, Correct logic errors.
Write the code, Test the code
float(item)
You pass an argument to the float( ) function and it returns the argument's value converted to a float.
int(item)
You pass an argument to the int() function and it returns the argument's value converted to an int.
Line continuation character
a backslash (\)
flowcharts
a diagram that graphically depicts the steps that take place in the program.
logic error
a mistake that does not prevent the program from running but causes it to produce incorrect results
variable
a name that represents a value stored in the computer's memory
numeric literal
a number that is written into a program's code
function
a piece of prewritten code that performs an operation
math operators
a programmer's tools for performing calculations
string
a sequence of characters that is used as data
algorithm
a set of well-defined steps for performing a task or solving a problem
escape character
a special character that is preceded with a backslash (\), appearing inside a string literal
psuedocode
an informal language that has no syntax rules and is not meant to be compiled and executed, but instead used to create models, or mock-ups, of programs
horizontal tab
appears after every eighth character
end-line comment
appears at the end of a line of code
string concatenation
appends one string to another: print('This is ' + 'one string.')
The equal sign (=) in Python is known as the _______
assignment operator
A(n) ________ makes a variable reference a value in the computer's memory.
assignment statement
What does a professional programmer usually do first to gain an understanding of a problem?
by working directly with the customer.
data types
categorize value in memory
escape character \\
causes a backslash character to be printed
escape character \"
causes a double quote mark to be printed
escape character \'
causes a single quote mark to be printed
escape character \t
causes output to skip over to the next horizontal tab position
escape character \n
causes the output to be advanced to the next line
Multiple arguments to a function are separated by
commas
format specifier
contains special characters specifying how the numeric value should be formatted:
assignment statement
create a variable and make it reference a piece of data. (age = 25) (variable = expression)
argument
data passed to a function.
Input
data the program receives
print function
displays output in a Python program.
If you want a string literal to contain either a single-quote or an apostrophe as part of the string, you can enclose the string literal in ______ marks.
double-quote
A string literal in Python must be enclosed in
either single-quotes or double-quotes
If you do not want the print function to start a new line of output when it finishes displaying it output, you can pass the special argument:
end=' '
An unexpected error that causes a running program to halt if it is not solved properly is called a(n)
exception
debug
find and correct coding errors.
Suppose the following statement is in a program: price = 99.0. After this statement executes, the price variable will reference a value of this data type
float
When an operation is performed on two float values, the result will be:
float
A numeric literal that is written with a decimal point is considered a(n)
float (1.5, 3.14159, 5.0)
What is the difference between floating-point division and integer division?
floating point division produces a floating point result. integer division produces an integer rounded to a number closest to 0 as output.
format specifier setting decimal precision to two spaces:
format(12345.6789, '.2f')
A ______ is a piece of prewritten code that performs an operation
function
When a value in memory is no longer referenced by a variable, it is automatically removed through a process known as _____
garbage collection
When a value in memory is no longer referenced by a variable, the Python interpreter automatically removes it from memory through a process known as:
garbage collection
This built-in function can be used to read input that has been typed on the keyboard
input()
Computer programs typically perform what three steps?
input, process, output
When an operation is performed on two int values, the result will be:
int
A numeric literal that is written as a whole number with no decimal point is considered a(n):
int (7, 124, -9)
When an integer is stored in memory, it is classified as a(n) _______, and when a real number is stored in memory, it is classified as a(n) _______.
int, float
A _____________ is a single function that the program must perform in order to satisfy the customer.
software requirement
A ______ is a sequence of characters.
string
calling
term used by programming to indicate the execution of a function
ovals in flowcharts
terminal symbols used to mark the starting and ending points of a program in a flowchart
When an operation is performed on an int and a float:
the int value will be temporarily converted to a float and the result will be a float.
Python also allows you to enclose string literals in ____________________ when the string contains both single and double quotes.
triple quotes (either """ or ''')
Variable reassignment
typically means to change the value of a variable based on its current value.
Variable names which would be legal in Python:
units_per_day, dayOfWeek, June1997
parallelograms in flowcharts
used as input and output symbols representing steps in which the program reads input or displays output
rectangles in flowcharts
used as processing symbols representing the steps in which the program performs some process on data, such as a mathematical calculation.
a _____ is any hypothetical person using a program and providing input for it.
user
A ______ is a name that references a value in the computer's memory
variable
string literal
when a string appears in the actual code of a program
Nested function calls
where one function calls another
In Python the first character of a variable name cannot be a number
True
Multiplication, floating-point division, integer division, and remainder operators have the same precedence
True
The float() function can be used to convert an int value to a float
True
You cannot use one of Python's key words a variable name.
True
The process of designing a program:
Understand the task the program is to perform, and Determine the steps that must be taken to perform the task.
When operators share an operand, the operator with the higher ______ is applied first.
precedence
print statement
print('string expression')
floating point as percentage multiplied by 100
print(format(0.5, '%'))
floating point as percentage with 0 as precision
print(format(0.5, '.0%'))
comma separator in format specifier
print(format(12345.6789, ',.2f'))
format specifier including a minimum field width
print(format(12345.6789, '12,.2f'))
formatting in scientific notation
print(format(12345.6789, 'e')) OR print(format(12345.6789, '.2e'))
integer printed with a comma separator
print(format(123456, ',d'))
integer printed with a comma separator in a field that is 10 spaces wide
print(format(123456, '10,d'))
integer printed in a field 10 spaces wide
print(format(123456, '10d'))
integer printed with no special formatting
print(format(123456, 'd'))
An informal language that has no syntax rules and is not meant to be compiled or executed is called ______
pseudocode
Tools used by programmers to create models of programs
pseudocode and flowcharts
exponent operator
raises a number to a power
input function
reads a piece of data that has been entered at the keyboard and returns that piece of data, as a string, back to the program; variable = input(prompt)
When a variable represents a value in the computer's memory, we say that the variable ______ the value.
references
item separator
sep=' ' (print('one', 'two', 'three', sep=' '))
character used to enclose string literals
single-quotation or double-quotation marks
You can use __________ marks to enclose a string literal that contains double quotes as part of the string.
single-quote
Who is a programmer's customer?
Any person, group, or organization that is asking you to write a program.
What is a format specifier and why is it used?
Because numbers are used in a variety of ways, such as in percentages and currency, it is used to output numeric data in a form that is relevant to the program.
Output
Data that has been processed into a useful format.
The Program Development Cycle
Design the program, Write the code, Correct syntax errors, Test the program, Correct logic errors; back to beginning
operands
The values on the left and right of the math operator
An expression that uses operands of different data types is called a ______
mixed-type expression
Variable naming rules
no Python key words, cannot contain spaces, first character must be a letter or underscore, preceding characters can be letters, numbers, or underscores, and uppercase and lowercase characters are distinct.
newline character
not seen, but causes the output to advance to the next line.
comments
notes of explanation that document lines or sections of a program. Part of the program, but ignored by the Python interpreter. Intended for people who may be reading the source code.
In the expression 12 + 7, the values on the right and left of the + symbol are called
operands
symbols in flowcharts
ovals, parallelograms, and rectangles
math expression
performs a calculation and gives a value
