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Commite9cf80b

Browse files
committed
Made suggested changes
- added hints.- improved wording on "More List Functions and Methods", now it's shorter.- fixed mistake on "second smallest element" exercise that prevented progress.- still missing MessageSteps, been struggling making them work.
1 parentb61b52d commite9cf80b

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‎backend/main/chapters/c06_lists.py‎

Lines changed: 93 additions & 23 deletions
Original file line numberDiff line numberDiff line change
@@ -894,6 +894,14 @@ def program(self):
894894
x.append(x.pop(0))
895895
print(x)
896896

897+
hints="""
898+
Moving the first element to the end requires two things: removing the first element, and adding it to the end.
899+
Which function/method can remove and return the first element?
900+
Then which function/method can add that element to the end?
901+
You need to use `pop` and `append`.
902+
Make sure you choose the line that applies these two operations in the right order!
903+
"""
904+
897905
classsubscript_assignment_exercise(VerbatimStep):
898906
"""
899907
Good job. For the next exercise, start with the same incomplete program:
@@ -914,6 +922,15 @@ def program(self):
914922
x[len(x)-1]=x[0]
915923
print(x)
916924

925+
hints="""
926+
Which function/method allows you to assign a value to a specific position in the list?
927+
You need to use subscript assignment.
928+
How do you assign a value to the last position in `x`?
929+
You need to use `len(x)` to access the last element.
930+
Which line in the list above involving `len(x)` accesses the last position correctly?
931+
Remember the list index starts counting from 0.
932+
"""
933+
917934
classnegative_index_concatenation_exercise(VerbatimStep):
918935
"""
919936
Excellent!
@@ -948,6 +965,16 @@ def program(self):
948965
y=x+ [x[0]]
949966
print(y)
950967

968+
hints="""
969+
Which function/method allows you to create a new list?
970+
You may be tempted to use `append` but that modifies the original list `x`.
971+
You need to use `+`. Remember this requires two lists.
972+
Start with the original list `x`. Then add another list to it.
973+
How do you get the first element of `x`? And then turn it into a second list?
974+
`x.pop(0)` will give us the first element, but it modifies the original list, which we need unchanged.
975+
Which line from the list above correctly turns the first element into a second list?
976+
"""
977+
951978
classremove_exercise(VerbatimStep):
952979
"""
953980
Great work. Now the final exercise:
@@ -967,6 +994,15 @@ def program(self):
967994
x.pop(x.index(0))
968995
print(x)
969996

997+
hints="""
998+
`x.remove(0)` finds the first occurrence of `0` in `x` and removes it.
999+
What other function/method can remove an element from a list?
1000+
`pop` can remove an element, but it requires an index.
1001+
Is there a function/method that can find the index of the first occurrence of an element?
1002+
`index` can do that.
1003+
Which line from the list above applies these two operations in the correct order?
1004+
"""
1005+
9701006
final_text="""
9711007
Great job!
9721008
"""
@@ -988,9 +1024,9 @@ class count_in_sorted_sum(VerbatimStep):
9881024
as you've now learned valuable fundamental skills. For example, you can use `in` to check if a list contains 5,
9891025
but there's no similarly easy way to check for a number bigger than 5.
9901026
991-
Now you will solve another set of four exercisesabout these newfunctions and methods, just like before.
992-
Again, correct and incorrectsolutionsare mixed together, and you must choose the correct line of code,
993-
replace the indicated part with it in your solution and run your code.
1027+
Now you will solve another set of four exercisesinvolving these newconcepts.
1028+
Again, correct and incorrectlines of codeare mixed together,
1029+
and you must choose the correct line from the list.
9941030
9951031
sum(len(x))
9961032
sum(range(x))
@@ -1010,35 +1046,41 @@ class count_in_sorted_sum(VerbatimStep):
10101046
x.count(1) > 0
10111047
x.count(1) > 1
10121048
1013-
First exercise:
1014-
1015-
Write a program that takes a list `x` of numbers and prints `True` if `1 in x`, prints `False` otherwise.
1016-
Here is the provided code for you to use. Replace the indicated part with a line from the list above, then run the code.
1049+
Here is a program:
10171050
10181051
__copyable__
10191052
x = [1, 2, 0, 3]
1020-
y = (insert_one_line_from_above)
1021-
print(y)
1053+
print(1 in x)
1054+
1055+
Replace the part `1 in x` with one line from the list above that does the same thing.
10221056
"""
10231057

10241058
program_in_text=False
10251059

10261060
defprogram(self):
10271061
x= [1,2,0,3]
1028-
y=x.count(1)>0
1029-
print(y)
1062+
print(x.count(1)>0)
1063+
1064+
hints="""
1065+
`1 in x` is `True` if `x` contains the number `1`, `False` otherwise.
1066+
What other function/method can tell us if `x` contains `1`?
1067+
`count` can do that.
1068+
Which line from the list above involving `count` correctly detects `1 in x`?
1069+
If `x` contains `1`, then the count of `1` should be at least one.
1070+
That is, it must be greater than zero.
1071+
"""
10301072

10311073
classaverage_exercise(VerbatimStep):
10321074
"""
1033-
Excellent work! Next exercise:
1034-
1035-
Write a program that takes a list `x` of numbers and prints the average of all the numbers in `x`.
1036-
Here is the provided code for you to use. Replace the indicated part with a line from the list above, then run the code.
1075+
Excellent work! For the next exercise, start with this incomplete program:
10371076
10381077
__copyable__
10391078
x = [15, 12, -6, 3]
10401079
y = (insert_one_line_from_above)
10411080
print(y)
1081+
1082+
Replace the part after `y = ` with one line from the list above.
1083+
The final program should print the average of the numbers in `x`.
10421084
"""
10431085

10441086
program_in_text=False
@@ -1048,17 +1090,26 @@ def program(self):
10481090
y=sum(x)/len(x)
10491091
print(y)
10501092

1093+
hints="""
1094+
To calculate the average of numbers in `x` we need two things.
1095+
We need to add up all the numbers in `x`, and we need how many numbers in `x` there are.
1096+
Which two functions/methods can do that?
1097+
`sum` and `len`.
1098+
Which line from the list above correctly calculates the average?
1099+
The average is calculated by dividing the total sum by the number of elements.
1100+
"""
1101+
10511102
classsum_range_exercise(VerbatimStep):
10521103
"""
1053-
Good job! Next exercise:
1054-
1055-
Write a program that takes a positive number `x` and prints the value of the sum: `1 + 2 + 3 + ... + x`.
1056-
Here is the provided code for you to use. Replace the indicated part with a line from the list above, then run the code.
1104+
Good job! For the next exercise, start with this incomplete program:
10571105
10581106
__copyable__
10591107
x = 100
10601108
y = (insert_one_line_from_above)
10611109
print(y)
1110+
1111+
Replace the part after `y = ` with one line from the list above.
1112+
The final program should print the value of the sum: `1 + 2 + 3 + ... + x`.
10621113
"""
10631114

10641115
program_in_text=False
@@ -1068,26 +1119,45 @@ def program(self):
10681119
y=sum(range(x+1))
10691120
print(y)
10701121

1122+
hints="""
1123+
One function/method we need to use is already mentioned in the exercise.
1124+
It's `sum`. Which other function/method do we need?
1125+
How can we `sum` the numbers `1, 2, 3, ..., x`? If only we had a list of these numbers.
1126+
Since we are adding them up, a list of the numbers `0, 1, 2, 3, ..., x` would also work.
1127+
Which function/method gives us something similar to the list of numbers `0, 1, 2, 3, ..., x`?
1128+
Remember that `range(x)` is similar to `[0, 1, 2, ..., x - 1]`.
1129+
That's very close to what we need, but not quite.
1130+
Which line from the list above correctly uses `range` to give us `[0, 1, 2, ..., x]`?
1131+
"""
1132+
10711133
classsecond_smallest_in_list_exercise(VerbatimStep):
10721134
"""
10731135
Excellent. And the last one:
10741136
1075-
Write a program that takes a list of numbers `x` and prints the *second smallest value* in `x`.
1076-
Here is the provided code for you to use. Replace the indicated part with a line from the list above, then run the code.
1077-
10781137
__copyable__
10791138
x = [12, -6, 2, -1, 3]
10801139
y = (insert_one_line_from_above)
10811140
print(y)
1141+
1142+
Replace the part after `y = ` with one line from the list above.
1143+
The final program should print the *second smallest value* in `x`.
10821144
"""
10831145

10841146
program_in_text=False
10851147

10861148
defprogram(self):
1087-
x= [1,2,0,3]
1149+
x= [12,-6,2,-1,3]
10881150
y=sorted(x)[1]
10891151
print(y)
10901152

1153+
hints="""
1154+
To find the second smallest value in `x` we can order the numbers in `x` from smallest to largest.
1155+
Which function/method can order the numbers in `x` like that?
1156+
It's `sorted`.
1157+
Then how do we access the *second* element in `sorted(x)`?
1158+
Remember the list index starts counting from 0.
1159+
"""
1160+
10911161
final_text="""
10921162
Congratulations! You are now a master of list methods and functions!
10931163
"""

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