Python Final Exam

Question 1

Program

Answer 1

sequence of instructions that specifies how to perform a computation

Question 2

Computation

Answer 2

mathematical computation -> data processing, aka software

Question 3

Hardware

Answer 3

physical parts that make up a computer

Question 4

Typical hardware components

Answer 4

Central processing unit (CPU)
* Main memory (RAM)
* Secondary storage devices (HD)
* Input and output devices

Question 5

Application software

Answer 5

Programs that make computer useful for
business and users
* Word
* Excel
* Photoshop
* Outlook
* Chrome
* iTunes

Question 6

System Software

Answer 6

Operating system
* Controls hardware
* Windows, MacOS, Linux, IOS, Android
Utilities
* Enhance or protects the computer
* Anti-virus, 7-zip, Parallels
Software development tools
* Create and modify software
* IDLE, Visual Studio, IntelliJ IDEA

Question 7

Low-level language

Answer 7

Close in nature to machine language
* Computer architecture specific. Not portable.

FORTRAN, COBOL, and C

Question 8

High-level language

Answer 8

Allows simple creation of powerful and complex programs
* Agnostic to the computer architecture. Portable code.

Python, PHP, Java, C++, Ruby.

Question 9

What types of processes do we have?

Answer 9

Math, conditions, repetition

Question 10

Algorithm

Answer 10

set of step-by-step instructions that detail a process or
computation

(set of logical, well-defined rules or procedures for efficiently and
accurately solving a problem)

Question 11

Pseudocode

Answer 11

informal high-level description of the structure of an
algorithm
* Written in a combination of natural language and programming
language constructs.

Question 12

Flowchart elements

Answer 12

terminal symbol = oval
processing symbol = rectangle
decision symbol = diamond
input/output = slanted rectangle

Question 13

Python Advantages

Answer 13

High-level language
Extensible (lots of packages)
Versatile
Emphasis on style & readability
No semicolons/brackets –> mainly identation
interpreted NOT compiled (translate on the fly)

Question 14

Difference Interactive mode versus Python scripts

Answer 14

Interactive mode = “console”, won’t save
Python script saves code, end in .py, can be run from IDLE with run button

Question 15

IDLE

Answer 15

Integrated Development Program
Single program that provides tools to write, execute and test a program

Has interactive and scripting mode

Question 16

Function

Answer 16

prewritten code that performs a “blackbox” operation (e.g. print, max etc.)

Group of statements that exist within in a larger program

Question 17

Argument

Answer 17

any data that is passed to a function, e.g. “Hello again”

Question 18

Default type for input

Answer 18

Str

Question 19

Variable

Answer 19

letter or word(s) that represents data stored in
the computer’s memory.

Question 20

//

Answer 20

Floor division, divides two numbers and then returns the lower integer

Example

7//2 = 3
(7 divided by 2 is 3.5, and then rounded down)

Question 21

%

Answer 21

Modulo - retains remainder

For example

7 % 2 = 1
(because 7 divided by 2 is 3 with a remainder of 1)

Question 22

format function

Answer 22

.2f –> print(f” {number.2f}”)
,.2f –> comma and two decimal places
.0% –> percentage rather than decimal
,d –> adds commas for whole integers

Question 23

end and sep arguments. Give an example

Answer 23

print(number sep=”___”)
print(number end=”___”)
\n = new line
\t = insert tab

Question 24

Decision Structure

Answer 24

execute certain statements
only under certain circumstances.

Question 25

Conditional execution

Answer 25

execute statement only when the condition is true. Simplest form of Decision.

Question 26

Condition Control (while loop)

Answer 26

Number of loops/iterations is unknown, Boolean expression usually exits the loop

Question 27

Count controlled (for)

Answer 27

Based on a counter, number of loops is known

Question 28

Nested loops

Answer 28

Inner cycle cycles through each iteration for each outer loop inner loop iterates multiple times (faster) than outer loop iterations = inner loop * outer loop

Question 29

How to change items of a list?

Answer 29

a.append("new word") a.pop() --> deletes last item a[1] --> choose the index 1 a[4,6] --> selects index 4 and 5 a.insert(5, "banana") --> inserts banana at index 5 a.remove ("banana") --> removes all values with banana

Question 30

What can control structure be divided in?

Answer 30

sequence, selection, and iteration.

Question 31

Control structure

Answer 31

logical design that controls the order in which a set of statements execute

Question 32

What are short-circuit evaluators?

Answer 32

logical operator that evaluates its operands from left to right and stops as soon as the result of the entire expression is determined The two existing one's in Python: And/or

Question 33

Modularized program

Answer 33

Each task within the program is a function of its own

Question 34

Benefits of modularized program

Answer 34

simpler use, better testing and debugging, faster development, code can be reused

Question 35

Void function

Answer 35

executes a statement (e.g. prints a statement)

Question 36

Value-returning function

Answer 36

executes a statement and then returns a value back (e.g. input, integer, float function etc)

Question 37

Syntax void function

Answer 37

def function_name(): statement or def main(): function1() function2()

Question 38

top-down design

Answer 38

technique to break down algorithm into functions through decomposition (through hierarchy)

Question 39

Syntax value-returning function

Answer 39

def function_name(parameter1, parameter2): sum = parameter1+parameter2 return sum

Question 40

Final Parameter

Answer 40

local variable that receives an argument

Question 41

list

Answer 41

collection of items within an object, mutable

Question 42

element

Answer 42

an item in a list

Question 43

Syntax list

Answer 43

list1 = []

Question 44

tuple

Answer 44

similar to list, but immutable (no insert or append)

Question 45

enumerate function

Answer 45

adds counter to sequence listb = list(enumerate(lista)

Question 46

slice syntac

Answer 46

lista[start:stop:step]

Question 47

"in" operator in list

Answer 47

if x in lista:

Question 48

list methods

Answer 48

append(item) index(item) insert (index, item) sort() for n in list:

Question 49

average of a list

Answer 49

calculate total and divide by len(list)

Question 50

2-dimensional lists

Answer 50

nested lists, rows and columns, a = [[a,b,c], [1,2,3]] indexed by two indeces e.g. [2][2] = 3

Question 51

What does \ do in a string?

Answer 51

allows to break a statement into multiple line (similar to \n or \t)

Question 52

Can strings be indexed?

Answer 52

Yes

Question 53

Strings mutable or immutable?

Answer 53

Immutable, but can slice strings

Question 54

Dictionaries

Answer 54

store collection of data with key and value

Question 55

Syntax dictionary

Answer 55

dictionary = {k1:v1, k2:v2} or dict() function on a list

Question 56

Advantages dictionaries

Answer 56

keys must be unique, very fast

Question 57

How to retrieve values in dictionaries?

Answer 57

Use key, e.g. dictionary[key]

Question 58

Get method for dictionaries

Answer 58

dictionary.get(key, default) --> if key does not exist a default value is returned

Question 59

Iterate through dictionary

Answer 59

for key in dictionary: print(key) #prints the key print(dictionary[key]) #prints the value

Question 60

Set

Answer 60

object that stores a collection, all items must be unique

Question 61

Syntax Set

Answer 61

set1 = {} (but not key-value pairs) or set() function

Question 62

open file syntax

Answer 62

file_name = open(filename, mode)