关于while循环的问题。 我的代码有什么问题？

Question

The question requires me to construct a while loop to display the values of the Rating of an album playlist stored in the list PlayListRatings given that the score is less than 6 and the list PlayListRatings is given by: PlayListRatings = [10, 9.5, 10, 8, 7.5, 5, 10, 10].

My code is

PlayListRatings= [10,9.5,10,8,7.5,5,10,10]

NewPlayListRatings=[]


while(PlayListRatings[i]> 6):

    NewPlayListRatings.append(PlayListRatings[i])

    i=i+1
    

The output is [10, 9.5, 10, 8, 7.5]

But the suggested answer shows this:

PlayListRatings = [10, 9.5, 10, 8, 7.5, 5, 10, 10]
i = 0
Rating = PlayListRatings[0]
while(i < len(PlayListRatings) and Rating >= 6):
    Rating = PlayListRatings[i]
    print(Rating)
    i = i + 1

The output is slightly different from mine.

[10 9.5 8 7.5 5]

5 is included.

Can someone enlighten me on what's wrong with my code? Thank you.

Answer 1

To start with I'm not sure how you even managed to get an output from your code considering that you do not define i before using it in your while loop declaration.

Before referencing a value, in this case i , you must first declare that value. This is what the accepted answer is doing on the second line with: i = 0 .

Now, your loop condition is while(PlayListRatings[i]> 6) if you were to translate this to english it would say "loop as long as PlayListRatings[i] is greater than 6 . When the loop reaches the value 5 , your loop condition becomes while(5 > 6) , and since it is not, the code inside of the loop is not executed and then the loop terminates. That is why the 5 is not in the final list.

Answer 2

first of all its happens because you change the Rating variable before printing it and after checking it on while loop second, you think so hard! it's like C language code!

PlayListRatings = [10, 9.5, 10, 8, 7.5, 5, 10, 10]
[print(x) for x in PlayListRatings if x> 6]

or if you want to save the list

PlayListRatings = [10, 9.5, 10, 8, 7.5, 5, 10, 10]
new_list = [x for x in PlayListRatings if x> 6]
print(new_list)