cs workbook content

Question 1

**If the first index is greater than or equal to the second the result is an **

Such:
»> fruit = ‘banana’
»> fruit[3:3]
What is output?

Answer 1

what string indexing does this: the result is an empty string, represented by two quotation marks:

Question 2

when changing strings, what should you know?

Answer 2

(ig)strings are immutable in Python, it means that once a string is created, it cannot be changed or modified.

Question 3

Python has a function called “what?” which lists all the methods available for an object.

Answer 3

function dir does what?

Question 4

the method “what” takes a string and returns a new string with all uppercase letters.

How would I write this and know about it?

Answer 4

(ig) instead of the function syntax, upper(word), it uses the method syntax, word.upper().
The empty parentheses indicate that this method takes no argument.

word = ‘banana’
2
new_word = word.upper()
3
print(new_word)
4
​
BANANA

Question 5

explain the syntax of find() and explain its paramters

Answer 5

(ig)Syntax
string.find(value, start, end)

Parameter Values
Parameter Description
value Required. The value to search for
start Optional. Where to start the search. Default is 0
end Optional. Where to end the search. Default is to the end of the string

Question 6

The find() method returns what? if the value is not found.

Answer 6

(ig) -1

Question 7

The method finds the first occurrence of the specified value.

Answer 7

(ig) The find() method finds the first occurrence of the specified value.

Question 8

You will note that** startswith** requires what, so what

Answer 8

You will note that startswith requires case to match, so sometimes we’ll convert a line to lowercase using the lower method before we do any checking:
line = ‘Have a nice day’
line.startswith(‘h’)

print(line.lower())

print(line.lower().startswith(‘h’))
have a nice day
True

Question 9

Method that makes all the letters lowercased

Answer 9

(ig) string.lower()

Question 10

the string method **what? ** to count the number of times a string appears in a another string. How would I write this

Answer 10

(ig) string.count(‘aa’)

def countSS(word):
counter = word.count(‘ss’)
return counter

Question 11

What is used to format an integer, floating-point number, and string

Answer 11

(anw follows the statement)What does the following: %d, %g , and %s.

Question 12

What list method adds a new element to the end of a list, also a way to add to an empty list:

Answer 12

string.append does what and should know(don’t look on the bottom)
&raquo_space;> t = [‘a’, ‘b’, ‘c’]
»> t.append(‘d’)
»> t
[‘a’, ‘b’, ‘c’, ‘d’]

Question 13

What list method adds the specified list elements (or any iterable) to the end of the current list.

Parameter Description
iterable Required. Any iterable (list, set, tuple, etc.)

Answer 13

What does string.extend() do? What do you use on this?

fruits = [‘apple’, ‘banana’, ‘cherry’]

points = (1, 4, 5, 9)

fruits.extend(points)

print(fruits)
[‘apple’, ‘banana’, ‘cherry’, 1, 4, 5, 9]

> > > t1 = [‘a’, ‘b’, ‘c’]
t2 = [‘d’, ‘e’]
t1.extend(t2)
t1
[‘a’, ‘b’, ‘c’, ‘d’, ‘e’]

Question 14

What list method arranges the elements of the list from low to high:

Answer 14

What does string.sort do?() do(don’t look below)

> > > t = [‘d’, ‘c’, ‘e’, ‘b’, ‘a’]
t.sort()
t
[‘a’, ‘b’, ‘c’, ‘d’, ‘e’]

Question 15

Adding up the elements of a list is such a common operation that Python provides it as a built-in function

Answer 15

Explain and give me the connotation of using sum()

_
»> t = [1, 2, 3]
»> sum(t)
6

Question 16

If you know the index of the element you want to delete, you can use what: modifies the list and returns the element that was removed. If you don’t provide an index, it deletes and returns the last element.

Answer 16

What does string.pop() do?

-

> > > t = [‘a’, ‘b’, ‘c’]
x = t.pop(1)
t
[‘a’, ‘c’]
x
‘b’

Question 17

If you don’t provide an index for pop(), what happens?

Answer 17

(ig)If provide an index, it deletes and returns the last element, basically deletes the last item.

Question 18

If you don’t need the removed value like from pop(), you can use what?

Answer 18

What does del string[] do?

-
»> t = [‘a’, ‘b’, ‘c’]
»> del t[1]
»> t
[‘a’, ‘c’]

Question 19

If you know the element you want to remove (but not the index), you can use what?

The return value from this is None.

Answer 19

What does string.remove() do/return explanation?

> > > t = [‘a’, ‘b’, ‘c’]
t.remove(‘b’)
t
[‘a’, ‘c’]

Question 20

NT

To remove more than one element, you can use

Answer 20

(ig) you can use del with a slice index:

> > > t = [‘a’, ‘b’, ‘c’, ‘d’, ‘e’, ‘f’]
del t[1:5]
t
[‘a’, ‘f’]

Question 21

To convert from a string to a list of characters, you can use?

Answer 21

What does list(string) do?

> > > s = ‘spam’
t = list(s)
t
[’s’, ‘p’, ‘a’, ‘m’]

Question 22

The list function breaks a string into individual letters. If you want to break a string into words, you can use what?

Answer 22

What does string.split() do? What uses this?

-

> > > s = ‘pining for the fjords’
t = s.split()
t
[‘pining’, ‘for’, ‘the’, ‘fjords’]

s = ‘pining for the fjords’
t = s.split()
print(t)

print(t[2])
[‘pining’, ‘for’, ‘the’, ‘fjords’]
the

Question 23

An optional argument called a what? specifies which characters to use as word boundaries.

Answer 23

What does delimiter do?

-
The following example uses a hyphen as a delimiter:

> > > s = ‘spam-spam-spam’
delimiter = ‘-‘
t = s.split(delimiter)
t
[‘spam’, ‘spam’, ‘spam’]

> > > t = [‘pining’, ‘for’, ‘the’, ‘fjords’]
delimiter = ‘ ‘
s = delimiter.join(t)
s
‘pining for the fjords’

Question 24

A method that is the inverse of split. It takes a list of strings and concatenates the elements. This method is a string method, so you have to invoke it on the delimiter or anything else like” “ and pass the list as a parameter.

Answer 24

What does delimiter.join(string) do?

> > > t = [‘pining’, ‘for’, ‘the’, ‘fjords’]
delimiter = ‘ ‘
s = delimiter.join(t)
s
‘pining for the fjords’

Question 25

To concatenate strings without spaces, you can what as a delimiter.

Answer 25

(ig) To concatenate strings without spaces, you can use the empty string, ‘’, as a delimiter.

Question 26

In this example, Python only created one string object, and both a and b refer to it.
&raquo_space;> a = ‘banana’
»> b = ‘banana’
»> a is b
True
But when you create two lists, you get **how many objects: **
»> a = [1, 2, 3]
»> b = [1, 2, 3]
»> a is b
True or False

Answer 26

(ig) two objects, False

Question 27

An object with more than one reference has more than one name, so we say that the object is what? What should you about changing this “what”

Answer 27

(ig)An object with more than one reference has more than one name, so we say that the object is aliased.

If the aliased object is mutable, changes made with one alias affect the other:

> > > b[0] = 42
a
[42, 2, 3]

Question 28

difference between append and + operator

Answer 28

(ig) the append method modifies a list, but the + operator creates a new list:

Question 29

The method takes all items in an iterable and joins them into one string.

A string must be specified as the separator.

Answer 29

string.join(iterable)

describe and explain its parameter

Join all items in a tuple into a string, using a hash character as separator:
myTuple = (“John”, “Peter”, “Vicky”)

x = “#”.join(myTuple)

print(x)

John#Peter#Vicky

Question 30

The method adds an element to the set.

If the element already exists, the method does not add the element.

Answer 30

describe add() method, what do you use on for

-
thisset = {“apple”, “banana”, “cherry”}

thisset.add(“orange”)

print(thisset)
{‘orange’, ‘cherry’, ‘banana’, ‘apple’}

Question 31

The method removes the specified item from the set.

This method is different from the remove() method, because the remove() method will raise an error if the specified item does not exist, and the method will not.

Answer 31

Describe what uses the discard() method and the what’s special about it?

Question 32

The function returns a sorted list of the specified iterable object.

You can specify ascending or descending order. Strings are sorted alphabetically, and numbers are sorted numerically.

Note: You cannot sort a list that contains BOTH string values AND numeric values.

Answer 32

describe sorted()

a = (“h”, “b”, “a”, “c”, “f”, “d”, “e”, “g”)

x = sorted(a, reverse=True)

print(x)

[‘h’, ‘g’, ‘f’, ‘e’, ‘d’, ‘c’, ‘b’, ‘a’]

a = (“Jenifer”, “Sally”, “Jane”)
x = sorted(a, key=len)
print(x)

[‘Jane’, ‘Sally’, ‘Jenifer’]

Question 33

describe sorted() parameters

Answer 33

(ig)Parameter Description
iterable Required. The sequence to sort, list, dictionary, tuple etc.
key Optional. A Function to execute to decide the order. Default is None
reverse Optional. A Boolean. False will sort ascending, True will sort descending. Default is False

a = (“h”, “b”, “a”, “c”, “f”, “d”, “e”, “g”)
​
x = sorted(a, reverse=True)
​
print(x)
​
[‘h’, ‘g’, ‘f’, ‘e’, ‘d’, ‘c’, ‘b’, ‘a’]
​
a = (“Jenifer”, “Sally”, “Jane”)
x = sorted(a, key=len)
print(x)
​
[‘Jane’, ‘Sally’, ‘Jenifer’]

Question 34

.sort() vs sorted()

Answer 34

(ig) The sorted() function creates a new sorted list and leaves the original list unmodified.
The .sort() method sorts the original list, mutating it.

Question 35

The method sorts the list ascending by default.

You can also make a function to decide the sorting criteria(s).

Answer 35

what uses sort() method, and describe it

Question 36

What is the parameter Values of .sort()

Answer 36

(ig) Parameter Description

Syntax
list.sort(reverse=True|False, key=myFunc)

reverse Optional. reverse=True will sort the list descending. Default is reverse=False
key Optional. A function to specify the sorting criteria(s)

A function that returns the length of the value:
def myFunc(e):
return len(e)

cars = [‘Ford’, ‘Mitsubishi’, ‘BMW’, ‘VW’]

cars.sort(key=myFunc)

print(cars)

[‘VW’, ‘BMW’, ‘Ford’, ‘Mitsubishi’]

Question 37

What method returns a string where the first character is upper case, and the rest is lower case.

It uses a string

Answer 37

describe capitalize() method, and what do you use for it

Question 38

extra

It is also possible to use what when creating a new list.

Answer 38

what does/ how to use the list() constructor

thislist = list((“apple”, “banana”, “cherry”)) # note the double round-brackets
print(thislist)

Question 39

Describe set? List?

Answer 39

(ig) List is a collection which is ordered and changeable. Allows duplicate members.

Set is a collection which is unordered, unchangeable*, and unindexed. No duplicate members.
Set items are unchangeable, but you can remove and/or add items whenever you like.

Question 40

How do (+ operator) work on lists

Answer 40

(ig)Addition (+): List Concatenation
The + operator is used to concatenate two lists, meaning it joins them together.
It does not add the elements in the lists mathematically.

list1 = [1, 2, 3]
list2 = [4, 5, 6]
result = list1 + list2
print(result) # Output: [1, 2, 3, 4, 5, 6]

Question 41

How do (* operator) work on lists

Answer 41

(ig) Multiplication (*): List Repetition
The * operator repeats the list a specified number of times.
It does not multiply the elements in the list.

list1 = [1, 2, 3]
result = list1 * 3
print(result) # Output: [1, 2, 3, 1, 2, 3, 1, 2, 3]

Question 42

What function returns True if the specified object is of the specified type, otherwise False.

Parameter Description(object, type)
object Required. An object.
type A type or a class, or a tuple of types and/or classes

Answer 42

how does isinstance() works and explain it

What parameters are used?

x = isinstance(“Hello”, (str, float, int, str, list, dict, tuple))

print(x)
True

Question 43

What’s the range() syntax parameters

Answer 43

(ig) Parameter Description
start Optional. An integer number specifying at which position to start. Default is 0
stop Required. An integer number specifying at which position to stop (not included).
step Optional. An integer number specifying the incrementation. Default is 1

x = range(3, 20, 2)
for n in x:
print(n)

x = range(3, 6) for n in x:   print(n)

Question 44

The method that formats the specified value(s) and insert them inside the string’s placeholder.

The placeholder is defined using curly brackets: {}. Read more about the placeholders in the Placeholder section below.

This method returns the formatted string.

parameters:
value1, value2… Required. One or more values that should be formatted and inserted in the string.

The values are either a list of values separated by commas, a key=value list, or a combination of both.

The values can be of any data type.

What is used for this?

Answer 44

named indexes:

Describe and explain string.format(), what are use for the parameters

txt1 = “My name is {fname}, I’m {age}”.format(fname = “John”, age = 36)
#numbered indexes:
txt2 = “My name is {0}, I’m {1}”.format(“John”,36)
#empty placeholders:
txt3 = “My name is {}, I’m {}”.format(“John”,36)

print(txt1)
print(txt2)
print(txt3)

My name is John, I’m 36
My name is John, I’m 36
My name is John, I’m 36

txt = “For only {price:.2f} dollars!”
print(txt.format(price = 49))

txt = “For only {price:.2f} dollars!”
print(txt.format(price = 49))
txt = “For only {price:.2f} dollars!”
print(txt.format(price = 49))
For only 49.00 dollars!

Question 45

How can you make a dictionary to a list?

Answer 45

(ig) list(dictionary_name.keys())

If you want to print the keys in alphabetical order, you first make a list of the keys in the dictionary using the keys method available in dictionary objects

Question 46

extra

The method returns a string where some specified characters are replaced with the character described in a dictionary, or in a mapping table.

Parameter Description
table Required. Either a dictionary, or a mapping table describing how to perform the replace

If a character is not specified in the dictionary/table, the character will not be replaced.
If you use a dictionary, you must use ascii codes instead of characters.(don’t worry about how ascil code work now)

Answer 46

use a dictionary with ascii codes to replace 83 (S) with 80 (P):

What uses translate() and describe and its parameters with it

mydict = {83: 80}

txt = “Hello Sam!”

print(txt.translate(mydict))
Hello Pam!

Question 47

extra

The method returns a mapping table that can be used with the translate() method to replace specified characters.

Parameter Values
Parameter Description
x Required. If only one parameter is specified, this has to be a dictionary describing how to perform the replace. If two or more parameters are specified, this parameter has to be a string specifying the characters you want to replace.
y Optional. A string with the same length as parameter x. Each character in the first parameter will be replaced with the corresponding character in this string.
z Optional. A string describing which characters to remove from the original string.

Answer 47

Describe and how to use maketrans(), what parameters use it?

https://www.w3schools.com/python/ref_string_maketrans.asp

txt = “Hi Sam!”

x = “mSa”
y = “eJo”

mytable = str.maketrans(x, y)

print(txt.translate(mytable))
Hi Joe!

txt = “Hello Sam!”
mytable = str.maketrans(“S”, “P”)
print(txt.translate(mytable))

Hello Pam!

txt = “Good night Sam!”

x = “mSa”
y = “eJo”
z = “odnght”

mytable = str.maketrans(x, y, z)
print(txt.translate(mytable))
G i Joe!

Question 48

The method returns a view object. The view object contains the key-value pairs of the dictionary, as tuples in a list.

The view object will reflect any changes done to the dictionary

No parameters

When an item in the dictionary changes value, the view object also gets updated:

Bascially it does this dict_items([ ])

Answer 48

Describe and the parameters in items(). What do you use on it, and if the thing that you use it change, what happens?

car = {
“brand”: “Ford”,
“model”: “Mustang”,
“year”: 1964
}

x = car.items()

print(x)
dict_items([(‘brand’, ‘Ford’), (‘model’, ‘Mustang’), (‘year’, 1964)])

car = {
“brand”: “Ford”,
“model”: “Mustang”,
“year”: 1964
}

x = car.items()

car[“year”] = 2018

print(x)

car = {
“brand”: “Ford”,
“model”: “Mustang”,
“year”: 1964
}

x = car.items()

car[“year”] = 2018

print(x)

car = {
“brand”: “Ford”,
“model”: “Mustang”,
“year”: 1964
}
​
x = car.items()
​
car[“year”] = 2018
​
print(x)
​
dict_items([(‘brand’, ‘Ford’), (‘model’, ‘Mustang’), (‘year’, 2018)])

Question 49

The what? keyword is used to create small anonymous functions.
The same what? function can take any number of arguments, but can only have one expression.

The expression is evaluated and the result is returned.

Answer 49

Describe lambda

x = lambda a : a + 10
print(x(5))
15

x = lambda a, b, c : a + b + c
print(x(5, 6, 3))
14

Question 50

json.dumps vs json.loads

Answer 50

(ig) json.dumps: Python object → JSON string
json.loads: JSON string → Python object

Question 51

How to do parsing, Serialization?

Answer 51

Serialization=
some_string = json.dumps(student_data)

parsing=
some_data = json.loads(some_string)

Question 52

What method returns True if all the characters are digits, otherwise False. What is this used on?

Answer 52

What does this do:(used on strings) string.isdigit()

Question 53

Explain what is a frame?(don’t have to go all the way, just give a brief summary)

Answer 53

a frame is a structure that represents a single execution context for a function call. Each time a function is called, Python creates a new frame to store the state and details of that particular execution. Frames are essential for tracking variables, function calls, and the flow of execution in a program.

def add(x, y):
result = x + y
return result

def multiply(a, b):
return a * add(a, b)

print(multiply(2, 3))
When multiply(2, 3) is called, a frame for multiply is created, storing a=2 and b=3.
Inside multiply, add(a, b) is called, which creates a new frame for add, with x=2 and y=3.
The add function finishes, and its frame is removed, returning control back to multiply.
Finally, multiply finishes and its frame is removed after printing the result.

Question 54

With try and except, how to know the reason for exception?

Answer 54

(ig) To know the specific reason for an exception in a try-except block, you can use the as keyword to capture the exception object. The exception object provides details about the error, including the error message, which can help you understand why the exception occurred.
try:
# Code that might raise an exception
result = 10 / 0
except ZeroDivisionError as e:
print(“An error occurred:”, e
(variable can be named anything)

	Directly Print e: Printing e itself usually gives you the error message.
	**str(e) give you the reason for exception
	type(e) give you the type of the exception

Question 55

What’s an value error, is it an exception error?

Answer 55

An exception that occurs when a function receives an argument of the correct type but an inappropriate or invalid value. In other words, the data type is correct, but the specific value of the data is not acceptable for that function or operation.

int(“hello”) # Raises ValueError: invalid literal for int() with base 10: ‘hello’
a, b = [1, 2, 3] # Raises ValueError: too many values to unpack (expected 2)a, b = [1, 2, 3] # Raises ValueError: too many values to unpack (expected 2)

Question 56

How to raise error or exception, how to do it and explanation of it

Answer 56

(ig) Use raise keyword. The raise keyword raises an error and stops the control flow of the program.
Python Raise Syntax

raise {name_of_ the_ exception_class}

The basic way to raise an error is:

raise Exception(“user text”)

Raising an exception Without Specifying Exception Class
When we use the raise keyword, there’s no compulsion to give an exception class along with it. When we do not give any exception class name with the raise keyword, it reraises the exception that last occurred.

a = 5

if a % 2 != 0:
raise Exception(“The number shouldn’t be an odd integer”)
s = ‘apple’

try:
num = int(s)
except ValueError:
raise ValueError(“String can’t be changed into integer”)

	s = 'apple'

try:
num = int(s)
except:
raise