Final 6

Question 1

Does python’s “a variable is a pointer to a value” idea make it easier for variables to change size?

Answer 1

Yes

Question 2

According to lectures, when we change the value
of a variable, does the interpreter accomplish this by changing the value at the place pointed to by the variable, or does the interpreter accomplish this by moving the pointer over to point to another place in memory that has the new desired value.

a) first way b) second way

Answer 2

b) second way

Question 3

Can we change a variable’s type at runtime?

Answer 3

Yes

Question 4

According to lectures, are constants and variables declared the same way in Python?

Answer 4

Yes

Question 5

Would you expect = or == to be used in the expression of an if statement?

Answer 5

==

Question 6

How many ways are there to declare a variable in Python as expressed in class lectures?

Answer 6

One

Question 7

Is it normal to execute pseudo code?

Answer 7

No, pseudo code is not executable

Question 8

What happens when a variable (all of it, not a part of it) is assigned a value?

Answer 8

New value is put into some place of memory, and then the pointer value of the variable is changed to now point to this new place.

Question 9

What is one advantage of Pythons indention policy over C’s use of brackets
to show what code belongs within an if, etc.

Answer 9

Prevents disconnect between what the human reading the code understands it to mean and what the interpreter understands it to mean because it means the same thing to both. Less ambiguous.

Question 10

what it the output of

print(“aaaaa”,end=””);print(“bbb”,end=””);print(“c”);print(“d”)

Answer 10

aaaaabbbc

d

Question 11

what is the output of

print(1,2,3,sep=””)

Answer 11

123
(default sep is a space, sep=”” removes it)

Question 12

When doing expressions like (5 + 5.0)

the Python interpreter first turns the integer
5 into a float

a) True B) False

Answer 12

a) True, the integer 5 will be temporarily converted to a float and the output of the calculation will also be a float.

Question 13

Given the code

AA = []

write code with the append function

to make AA become the list with 2 elements, both equal to 2

Answer 13

AA = []
AA.append(2)
AA.append(2)
print(AA)
[2, 2]

Question 14

According to lectures, is it possible for roundoff
errors to cause problems with equality with real numbers

Answer 14

Yes

Question 15

Starting with aaa = [], add elements 1-500 using a while loop and the append function. This is to say that index 0 of aaa should be 1, index 1 index should be 2, etc., up to the 499 index which should be 500 .

Then, after this first while loop, write a second while loop that prints what is in aaa, one element per line, so that you get the following output:
aaa 1
aaa 2
aaa 3
.
.
.
aaa 500

Answer 15

aaa = []
i = 0

while i < 500:
i += 1
aaa.append(i)

i = 0
while i < 500:
print(“aaa “ + str(aaa[i]))
i += 1

Question 16

Given the starting code

Names =[“Dan”,”Sally”]
Quiz1Grades=[70,56]
Quiz2Grades=[60,62]
AveGrades=[]

write two lines of code which use a for loop
and the append function to set AveGrades to a list
where for each indes, i, AveGrades[i] is
(Quiz1Grades[i] + Quiz2Grades[i])/2.0

again, use the append function to do this

add a second for loop that prints out
Names[i],Quiz1Grades[i],Quiz2Grades[i],AveGrades[i]

all on one line, for the 2 indexes

In other words, the total code should result in

Dan 70 60 65.0
Sally 56 62 59.0

getting printed out

Answer 16

for i in range(len(Names)):
AveGrades.append((Quiz1Grades[i] + Quiz2Grades[i]) / 2.0)

for i in range(len(Names)):
print(Names[i], Quiz1Grades[i], Quiz2Grades[i], AveGrades[i])

Question 17

Given code

astring = “ James , Lamm : 12 , 19, 2021 “

write some lines of code using two “split” commands together
with the “strip”, “lower” commands together with “int” casts which
assign variables
FN
LN
Month
Day
Year
MonthPlusDay

to
james
lamm
12
19
2021
31

respectively. Note that you need to convert the Month and
Day to ints in order to add them up and put the
result in variable MonthPlusDay. Also note that lower
should be used to take out the caps.

Answer 17

astring = “ James , Lamm : 12 , 19, 2021 “

parts = astring.split(“:”)
names = parts[0].split(“,”)
dates = parts[1].split(“,”)

FN = names[0].strip().lower()
LN = names[1].strip().lower()
Month = int(dates[0].strip())
Day = int(dates[1].strip())
Year = int(dates[2].strip())

MonthPlusDay = Month + Day

print(“FN: “ + FN)
print(“LN: “ + LN)
print(“Month: “ + str(Month))
print(“Day: “ + str(Day))
print(“Year: “ + str(Year))
print(“MonthPlusDay: “ + str(MonthPlusDay))