control flow

Question 1

what are conditional statments

Answer 1

This is the control flow of your program. In Python, your script will execute from the top down, until there is nothing left to run. It is your job to include gateways, known as conditional statements, to tell the computer when it should execute certain blocks of code. If these conditions are met, then run this function.

Question 2

what is boolean expression

Answer 2

n order to build control flow into our program, we want to be able to check if something is true or not. A boolean expression is a statement that can either be True or False.

Question 3

what does a Relational operators do

Answer 3

Relational operators compare two items and return either True or False. For this reason, you will sometimes hear them called comparators.

Question 3

what does == and != do

Answer 3

Equals: ==
Not equals: !=
1 == 1 # True

2 != 4 # True

3 == 5 # False

‘7’ == 7 # False

Question 3

is Friday is the best day of the week a boolean expression

Answer 3

No, this statement is an opinion and is not objectively True or False

Question 3

how do we create booleans

Question 4

why does True and False appear in different color

Answer 4

This is because True and False are their own special type: bool.

True and False are the only bool types, and any variable that is assigned one of these values is called a boolean variable.

Boolean variables can be created in several ways. The easiest way is to simply assign True or False to a variable:

set_to_true = True
set_to_false = False

Question 5

how do you create a boolean varible

Answer 5

Boolean variables can be created in several ways. The easiest way is to simply assign True or False to a variable:

set_to_true = True
set_to_false = False

Question 6

how do you variable equal to a boolean expression.

Answer 6

bool_one = 5 != 7
bool_two = 1 + 1 != 2
bool_three = 3 * 3 == 9
These variables now contain boolean values, so when you reference them they will only return the True or False values of the expression they were assigned.

print(bool_one) # True

print(bool_two) # False

print(bool_three) # True

Question 7

What is an if statement

Answer 7

If “it is raining” == True then the rest of the conditional statement will be executed and you will bring an umbrella.

Question 8

what is the colon : used for in if statments

Answer 8

if is_raining:
print(“bring an umbrella”)

You’ll notice that instead of “then” we have a colon, :. That tells the computer that what’s coming next is what should be executed if the condition is met.

Question 9

what are all the other relational operator symbols

Answer 9

> greater than
>= greater than or equal to
< less than
<= less than or equal to

Question 10

How would you set a write a program that checks if our users are over 13 when showing them a PG-13 movie

Answer 10

if age <= 13:
print(“Sorry, parental control required”)

This function will take the user’s age and compare it to the number 13. If age is less than or equal to 13, it will print out a message.

Question 11

what is an boolean operateor

Answer 11

you can build larger boolean expressions using boolean operators. These operators (also known as logical operators) combine smaller boolean expressions into larger boolean expressions.

Question 12

what are the 3 boolean operators

Answer 12

• and
• or
• not

Question 13

what does ( and ) boolean operator do

Answer 13

and combines two boolean expressions and evaluates as True if both its components are True, but False otherwise.

(1 + 1 == 2) and (2 + 2 == 4) # True

Question 14

what does the boolean opertor ( or ) do

Answer 14

The boolean operator or combines two expressions into a larger expression that is True if either component is True.

Question 15

does only one statment need to be true for the whole or statment to be true

Answer 15

yes - Oranges are a fruit or apples are a vegetable.

This statement is composed of two expressions: oranges are a fruit which is True and apples are a vegetable which is False. Because the two expressions are connected by the or operator, the entire statement is True. Only one component needs to be True for an or statement to be True.

Question 16

what is the ( not )

Answer 16

when applied to any boolean expression it reverses the boolean value. So if we have a True statement and apply a not operator we get a False statement.

not True == False
not False == True

Question 17

how would we add a not operator in pyhton

Answer 17

we add the not operator to the very beginning of the statement. Let’s take a look at some of those:

not 1 + 1 == 2 # False
not 7 < 0 # True

Question 18

what is an example of not

Answer 18

if not gpa >= 2.0:
print (“Your GPA is not high enough to graduate.”)

Question 19

what is the esle statment used for

Answer 19

else statements allow us to elegantly describe what we want our code to do when certain conditions are not met.

else statements always appear in conjunction with if statements. Consider our waking-up example to see how this works:

if weekday:
print(“wake up at 6:30”)
else:
print(“sleep in”)

Question 20

what is a else if statment (elif)

Answer 20

An elif statement checks another condition after the previous if statements conditions aren’t met

Question 21

what is can example of ( elif )

Answer 21

print(“Thank you for the donation!”)

if donation >= 1000:
print(“You’ve achieved platinum status”)
elif donation >= 500:
print(“You’ve achieved gold donor status”)
elif donation >= 100:
print(“You’ve achieved silver donor status”)
else:
print(“You’ve achieved bronze donor status”)

Take a second to think about this function. What would happen if all of the elif statements were simply if statements? If you donated $1100.00, then the first three messages would all print because each if condition had been met.

But because we used elif statements, it checks each condition sequentially and only prints one message. If I donate $600.00, the code first checks if that is over 1000, which it is not, then it checks if it’s over 500, which it is, so it prints that message, then because all of the other statements are elif and else, none of them get checked and no more messages get printed.