C4: Python for Data Science, AI & Development

Question 1

str()

Answer 1

String data type object.

Question 2

int()

Answer 2

Integer data type object.

Question 3

float()

Answer 3

Floating Point data type object.

Question 4

list()

Answer 4

Returns a list of the elements in an object.

E.g.,

Var = “Panks”
list(Var) : (“P”,”a”,”n”,”k”,”s”)

Question 5

int(3.55):?

Answer 5

3

Here you are casting a floating point through a integer data type, which may have strange results.

Question 6

float(15):?

Answer 6

15.0

Here you are casting a integer into a floating point data type.

Question 7

str(4.558):?

Answer 7

“4.558”

Here you are casting a floating point number into a string data type

Question 8

What are the two Boolean expressions in Python?

Answer 8

True & False*.

They must be camel case.

Question 9

int(True):?

Answer 9

1

Question 10

int(False):?

Answer 10

0

Question 11

bool(1):?

Answer 11

True.

Question 12

bool(0):?

Answer 12

False.

Question 13

What is an Operand?

Answer 13

The thing to be operated on.

Question 14

What is an Operator?

Answer 14

What the Operand opperates on.

Question 15

type()?

Answer 15

Returns the data type of variable.

Good for debugging.

Question 16

What’s Typecasting?

Answer 16

Converting one data type into another.

Question 17

Define Tuple.

Answer 17

1) An Ordered set of numbers.
2) Where the order cannot change.

• The sequence cannot be changed.
• Set is finite.
• Set may contain duplicates.

Question 18

n-tuple

Answer 18

(X1, … , Xn)

Question 19

What does RegEx mean?

Answer 19

Regular Expression.

• A Python module.
• A tool for matching and handling strings.

Question 20

> > > import re

Answer 20

Imports the Regular Expression module built into Python 3.

Question 21

Concatenation

Answer 21

Combines strings.

Question 22

Major Data Type Objects in Python.

Answer 22

Integers
Floating Points
Strings
Booleans

Question 23

Coupoud Data Type Objects? - Python

Answer 23

• Lists
• Tuples

Question 24

Tuples syntax? - Python

Answer 24

var = (X1,X2,…,…,Xn)

Question 25

For var = (X1,X2,…,…,Xn),
var[0] returns?

Answer 25

X1

Question 26

Slicing syntax? - Python

Answer 26

[ n1:n2:n3]

Where:
* n1 = The first index position to return.
* n2 = The last index position to pull, +1.
* n3 = The stride, if any.

Question 27

Immutable? - Python

Answer 27

Cannot be changed.

E.g.,
* Strings.
* Tuples.

Question 28

List syntax? - Python

Answer 28

var = [X1,X2,…,…,Xn]

Question 29

Difference between Lists and Tuples?

Answer 29

Lists are mutable. Tupples are not.

Question 30

var = [33,55,2,10]
var.extend([9,19])
?

Answer 30

print(var) :
[33,55,2,10,9,19]

Question 31

var = [33,55,2,10]
var.append([9,19])
?

Answer 31

print(var) :
[33,55,2,10,[9,19]]

Question 32

var = [33,55,2,10]
del(var[1])
?

Answer 32

var = [33,2,10]

Question 33

What method would you use to convert a string to a list?

Answer 33

.split()

E.g.,

str(“The rain in spain”)
str2 = str.split()
str2 = [“The”,”rain”,”in”,”spain”]

() is blank, the delimiter is space. Otherwise, pass in a delimiter, such as a colon.

Question 34

Define Aliasing.

Answer 34

Multiple names refering to the same object.

Question 35

A = [X1,X2,…,…,Xn]
B = A
list(B) = ?

Answer 35

[X1,X2,…,…,Xn]

Question 36

A = [X1,X2,…,…,Xn]
B = A[:]
A[2] = 100

list(A) = ?
list(B) = ?

Answer 36

A = [X1,X2,100,…,…,Xn]
B = [X1,X2,…,…,Xn]

A[:] clones the list in variable A.

Question 37

copy() - Python

Answer 37

A Method used to create a shallow copy of a list.

Question 38

count() - Python

Answer 38

A Method used to count the number of occurrences of a specific element in a list.

Question 39

Define these list methods:

Below, let “var”, be any variable that holds a list:

var.pop()
var.reverse()
var.sort
var.remove()
var.insert()
var.count()
var.copy()

Answer 39

• pop() method is another way to remove an element from a list in Python. It removes and returns the element at the specified index. If you don’t provide an index to the pop() method, it will remove and return the last element of the list by default
• The reverse() method is used to reverse the order of elements in a list
• The sort() method is used to sort the elements of a list in ascending order. If you want to sort the list in descending order, you can pass the reverse=True argument to the sort() method.
• To remove an element from a list. The remove() method removes the first occurrence of the specified value.
• The count() method is used to count the number of occurrences of a specific element in a list in Python.
• The copy() method is used to create a shallow copy of a list.

Question 40

Dictionaries object syntax?

Answer 40

{'A':'a','B':'b',...,...,'N':'n'}

Question 41

Dictionary attributes.

Answer 41

• Keys must be unique.
• Keys are immutable.
• –
• Values are mutable
• Values don’t have to be unique.

Question 42

Assume:
{'Key1':'Value1','Key2','Value2',...,...,'KeyN','ValueN'}.
–
If:
Dict['Key2'] :

Answer 42

Value2

Question 43

Assume:
{'Key1':'Value1','Key2','Value2'}.
–
If:
Dict['New1'] = 100 :

Answer 43

{'Key1':'Value1','Key2','Value2','New1':100}.

Question 44

Assume:
{'Key1':'Value1','Key2':'Value2','New1':100}.
–
If:
del(Dict['Key1']) :

Answer 44

{‘Key2’:’Value2’,’New1’:100}

Question 45

Assume:
{'A':'a','B':'b',...,...,'N':'n'}
–
Query this Dictionary for B.

Answer 45

'B' in Dict returns True

Question 46

Dict.keys() : ?

Answer 46

This method lists all the keys in the Dictionary.

Question 47

Dict.values() : ?

Answer 47

This method lists all the values in the Dictionary.

Question 48

Set properties?

Answer 48

• Unordered.
• Containes no duplicate values.

Question 49

Set object syntax?

Answer 49

{3,1,2,...,...,N}

Question 50

Typecast a List into a Set.

Answer 50

set(list[x,y,z])

Question 51

Assume:
var = [3,58,5,5,10,10,8,6]
–
set(var) : ?

Answer 51

{3,58,5,10,8,6}

Note: A set cannnot contain duplicates. They are removed from the list.

Question 52

Assume:
var = {'lake','fire','water'}
–
var.add('smores')
var : ?

Answer 52

{'lake','fire','water','smores'}

Question 53

Assume:
var = {'lake','fire','water','smores'}
–
var.add('fire')
var : ?

Answer 53

var = {'lake','fire','water','smores'}

*Note: A set cannnot contain duplicates. “fire’ cannot be added.

Question 54

Assume:
var = {'lake','fire','water','smores'}
–
var.remove('fire')
var : ?

Answer 54

var = {'lake','water','smores'}

Question 55

Assume:
var = {'lake','fire','water','smores'}
–
‘lake’ in var: ?

Answer 55

True

Question 56

Set Theory - Intersection

Assume:
Set1 = {1,2,3,4}
Set2= {3,4,5,6}

Instruct Python to find the intersection of both sets.

Answer 56

Set3 = Set1 & Set2
~~~
Set3 : {3,4}

Question 57

Set Theory - Union

Assume:
Set1 = {1,2,3,4}
Set2= {3,4,5,6}

Instruct Python to find the union of both sets.

Answer 57

Set3 = Set1.union(Set2)
~~~
{1,2,3,4,5,6}

Question 58

What method clears all the entries from a Dictionary?

Answer 58

var.clear()

Question 59

List the six common Comparison Operators.

Answer 59

A == B - Is A equal to B?
A != B - Is A not equal to B?
A > B - Is A greater than B?
A < B - Is A less than B?
A >= B - Is A greater or equal to B?
A <= B - Is A less or equal to B?

Question 60

Comparison Operators return what?

Answer 60

True or False.
These are boolean.

Question 61

‘Baxter’ == ‘Baker’: ?

Answer 61

False
~~~
Note: String data types can be compared.

Question 62

if syntax?

Answer 62

if(condition) : Execute if true.
______Indented code.
______Indented code.
~~~
Note: Indents are required.

Question 63

if / else syntax?

Answer 63

if(condition) : Execute if true.
______Indented code.
______Indented code.
else: Execute if above is false.
______Indented code.
______Indented code.
~~~
Note: Indents are required.

Question 64

if / elif / else syntax?

Answer 64

if(condition) : Execute if true.
______Indented code.
______Indented code.
elif(condition) : Execute if above is false & this is true.
______Indented code.
______Indented code.
else: Execute if both above are false.
______Indented code.
______Indented code.
~~~
Note: Indents are required.

Question 65

Logic Operators ?

Answer 65

not()
or()
and()

Python supports these three logic operators.

Question 66

if(True) and (False): ?

Answer 66

False

Question 67

if(True) or (False): ?

Answer 67

True

Question 68

range(N)
or
range(0,N)

Answer 68

[0,1,2,…,…,N-1]

Note:
* The last value of arange function is always one less than the number input into the function.
* A range sequence always starts at 0.
* N must be a an whole number.

Question 69

range(10,15) : ?

Answer 69

[10,11,12,13,14]

Question 70

i in for loops?

Answer 70

Index or increment.

Question 71

Incement i by 1.
Decrement i by 5.

Answer 71

i += 1
i -= 5

Question 72

for syntax?

Answer 72

for counter in iterable object :
______Indented code.
______Indented code.
~~~
Note:
* for will increment the “counter” at the end of each loop.
* “counter” can be any variable that can hold an integer data type. It is usualy i.
* It is a temporary variable that is constrained in scope to the loop.

Question 73

while syntax?

Answer 73

while some conditional True :
______Indented code.
______Indented code.

Note:
* It is not uncommon to itterate some counter variable within the while loop.

Question 74

list(enumerate(range(11))) : ?

Answer 74

[(0, 0),
(1, 1),
(2, 2),
(3, 3),
(4, 4),
(5, 5),
(6, 6),
(7, 7),
(8, 8),
(9, 9)
(10,10)]]

Question 75

Function syntax ?

Answer 75

def function_name(Argument(s)):
______”””
______Notes
______”””
______Indented code.
______return b

~~~
Note:
* Functions cannot have an empty body. Use none in the body satsify this requirement that the function not be blank.
* You do not have to define a return in a function.

Question 76

Do Local Variables confilict with Global Variables?

Answer 76

No.
Variables inside a functon do not change variables outside a function, even if they have the same name.

Question 77

What will Python do if if finds an undefined variable in a function?

Answer 77

Check for the variable in the global scope.

Question 78

What does pass do in a function?

Answer 78

• Acts as a temporary placeholder for future code.
• It ensures that the code remains syntactically correct, even if it doesn’t do anything yet.
• Doesn’t perform any meaningful action. When the interpreter encounters “pass”, it simply moves on to the next statement without executing any code.

Question 79

Define Global Scope variables.

Answer 79

Variables defined outside functions; accessible everywhere.

Question 80

Define Local Scope variables.

Answer 80

Variables inside functions; only usable within that function.

Question 81

What does global do in a function?

Answer 81

Changes the scope of a variable in the function from local to global.
Meaning that it can be referenced even after the function has completed.

Question 82

How would you modify the following function to allow you to pass in a variable number of arguments?
~~~
def a_function(argument):
______”””
______Notes
______”””
______Indented code.
______return b

Answer 82

Place an asterisk before the argument.
~~~
E.g., def a_function( *argument):

Question 83

Try syntax?

Answer 83

try:
______code or pass
except Exception:
______code or pass
except Exception:
______code or pass
else:
______code or pass
finally:
______code or pass

Question 84

Complete the sentence:
Methods are “…” with Objects.

Answer 84

…how you change or interact…

Question 85

Class > Object > ? > Method

Answer 85

Attribute.

Question 86

? > Object > Attribute > Method

Answer 86

Class

Question 87

Class > ? > Attribute > Method

Answer 87

Object

Question 88

Class > Object > Attribute > ?

Answer 88

Method

Question 89

A class is a template for?

Answer 89

Objects.

Question 90

Class syntax?

Answer 90

class className():

______class_attribute = value

______def __init__(self, attribute1, attribute2, …):
____________self.attribute1 = attribute1
____________self.attribute2 = attribute2
____________...

______def method1(self, parameter1, parameter2, ...): \_\_\_\_\_\_\_\_\_\_\_\_Method logic \_\_\_\_\_\_\_\_\_\_\_\_…`

~~~
* Class attributes (shared by all instances).
* Constructor method (initialize instance attributes).
* Instance methods (functions). Do not have to have a value passed.

Question 91

An objects attributes define it’s?

Answer 91

State.
A.k.a., The data that describes the object.

Question 92

An objects methods define it’s?

Answer 92

Behavior.
A.k.a., Actions assigned to the object that can change it’s state.

Question 93

An Object is an … of a Class?

Answer 93

Instance.

Question 94

Name the two loop controls.

Answer 94

Break.
Continue.

Question 95

What does dir(object) do?

Answer 95

Returns all properties and methods of the specified object, without the values.

Question 96

Open a file syntax?

Answer 96

open(*…/path/filename.txt,‘x’)
~~~
Where:
* *The value of x may be:
* r for reading mode.
* w for writing mode.
* a for appending mode.

Question 97

fileObject.name() returns?

Answer 97

The name of the file in the file object.

Question 98

Open the following file in append mode inside a file object named darth :
~~~
…/path/tothe.darkside

Answer 98

with open('…/path/tothe.darkside','a') as darth

Question 99

fileObject.read() ?

Answer 99

Reads the entire content of the file.
e.g., darth = vader.read()

Question 100

fileObject.read(x) ?

Answer 100

Reads x characters starting from the current position of the file pointer.
e.g., darth = vader.read(10)

Question 101

fileObject.readline() ?

Answer 101

Reads the contents of a file line by line.
Note, it remembers where it last read. Then itterates and reads the next line if called again. Also, if given an integer as an argument, it will read tham many posisitons of that line. But only from that line.

Question 102

fileObject.seek(x) ?

Answer 102

Moves the files pointer to a specific position in the file. Then reads that character.
The position is specified in bytes, so you’ll need to know the byte offset of the characters you want to read.

Question 103

fileObject.close() ?

Answer 103

Closes a file.
This is essential.
However, you should not have to use this if you are using the with method.

Question 104

Create a new file in the local directory named obiwan.master mapped to a file object named jedi.

Answer 104

with open('…/path/tothelight/obiwan.master','w') as jedi:

~~~
Note:
If the file requested by open does not exist in the directory, the action will create it.

Question 105

Dependencies is another name for ?

Answer 105

Libraries.

Question 106

.tell() does what?

Answer 106

Returns where the system caret ^ is in the file object.

Question 107

Diferentiate the following;
.readline() .readlines()

Answer 107

.readline():
This method returns one full line from the file object as a string.

.readlines():
This method returns all the line in a file object as a list.

Question 108

How do you querying a variable for it’s attributes and methods?

Answer 108

dir(var)

Question 109

Load pandas?

Answer 109

import pandas as pd

Question 110

With pandas imported:
df.head() does what?

Answer 110

Prints the first five rows of the data frame.

Question 111

• With pandas imported:
• Assume var is a dictionary.
  ~~~
  How would you cast the dictionary into a dataframe?

Answer 111

varInFrame = pd.DataFrame(var)

Question 112

With pandas imported:
When you cast a dictionary into a data frame, the values become?

Answer 112

Columns.
~~~
The keys become the column headers.

Question 113

With pandas imported:
How would you pull an entire column(s) from a data frame and make it a new object?

Answer 113

var = df [[ ‘key1’ , ‘key2’ , ‘key5’ ]]

Double brackets extracts a column by key (header)name.

Question 114

• With pandas imported +
• An active data frame, df:
  How would you reference cell a1?

Answer 114

df.iloc[0,0]

Question 115

With pandas imported:
Read a decks.csv into the data frame object, df.

Answer 115

df = pd.read_csv('decks.csv')

Question 116

• With pandas imported:
• Assume: data = [10, 20, 30, 40, 50]
  Create a series in series object s from this list.

Answer 116

s = pd.Series(data)

Question 117

Diferentiate,
print(df.iloc[n])
from
print(df.loc[n])

Answer 117

iloc accesses the row by position.
iloc[row_index, column_index]
i.e., index location.
Counts from 0.
~~~
loc acesses the row by label
loc[row_label, column_label]
Use method set_index() to set a columns contents as the index from the default.
Counts from 1.

Question 118

Pandas generally provides two data structures for manipulating data, They are?

Answer 118

Data Frames.
Series.

Question 119

df.iloc[1:3]
vs.
df.iloc[1,3]

Answer 119

The first slices out and returns rows 2 & 3.
The second selects the data a row 2 / column 3.

Question 120

What is df.iloc[0:2, 0:3] doing?

Answer 120

Slicing out the first two rows, three columns deep.

Question 121

NumPy stands for?

Answer 121

Numerical Python.

Question 122

NumPy is meant for working with?

Answer 122

• Arrays
• Linear algebra
• Fourier transforms
• Matrices

Question 123

The ‘Pandas library’ is built on?

Answer 123

The NumPy library.

Question 124

Syntax for making a 2D array in Python withNumPy?

Answer 124

my_2d_array = np.array [
_________________________[0,0,0,0,0,0],
_________________________[0,0,0,0,0,0],
_________________________[0,0,0,0,0,0],
_________________________[0,0,0,0,0,0],
_________________________[0,0,0,0,0,0],
_________________________],

Question 125

if var is an numpy array what do these methods do?
var.dtype
var.size
var.ndim
var.shape
var.dot()
var.mean()
var.max()
var.min()
var.std()

Answer 125

.dtype returns the type of the data stored in the array.
.size returns the number of elements in the array.
.ndim returns the number of dimensions of the array.
.shape returns the length of each dimension of the array.
.dot(a,b) returns the dot product of the np arrays a and b.
.mean() returns the mean value of the array.
.max() returns the max value of the array.
.std() returns the standard deviation of the array.

Question 126

np.pi ?

Answer 126

Return the value of pi.

Question 127

np.linspace(a,b,c)

Answer 127

np.linspace(a,b,c) returns a line (a list) starting at ‘a’ and ending at ‘b’ with ‘c’ evenly spaced intevals as a array. (Which include the intervals ‘a’ and ‘b’.

Question 128

What does URI stand for?

Answer 128

Uniform resource identifier.
This is distinct from a URL.

Question 129

What are the four HTTP methods?

Answer 129

GET: Retrieves data from the Server or API.
POST: Submits data to the Server or API.
PUT: Updates data on the Server or API.
DELETE: Deletes data on the the Server or in the API.

Question 130

What does the Requests library do?

Answer 130

Allows you to make HTTP 1.1 requests from within Python.

Question 131

A URL has three parts.
They are?

Answer 131

Scheme.
Address.
Path.

e.g.,

https://
www.google.com
/a/admin/login

Question 132

Which contanins which?
URL
URI

Answer 132

Uniform Resource Identifier > Uniform Resource Locator
or
URI {URL}

Question 133

What are the 5 HTTP response status code classes and their general meaning?

Answer 133

100: Info.
200: Success.
300: Make a choice.
400: Failure.
500: Big failure.

Question 134

HTML tags hierarchy?

Answer 134

Parent > Child > Decendent
Siblings = Siblings

Question 135

What is Beautiful Soup?

Answer 135

A module that facilitates webscraping.

Question 136

What does DOM stand for?

Answer 136

Document Object Model