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Albert Tomasura
11,041 Pointsslices.py Challenge Task 4/4
I tested the final piece ( def reverse_evens(items): ) in workspaces using the list in the example as: (items = [1, 2, 3, 4, 5]) and it produced [5, 3, 1], but it fails the challenge.
def first_4(items):
return items[:4]
def first_and_last_4(items):
return items[:4] + items[-4:]
def odds(items):
return items[1::2]
def reverse_evens(items):
return items[::-2]
Albert Tomasura
11,041 Points"You're on fire! Last one and it is, of course, the hardest. Make a function named reverse_evens that accepts a single iterable as an argument. Return every item in the iterable with an even index...in reverse. For example, with [1, 2, 3, 4, 5] as the input, the function would return [5, 3, 1]. You can do it!" - slices.py Challenge Task 4 of 4
Thanks for the help, Aryan. I wish they included those three checks to the Task description.
3 Answers
unseized
28,529 PointsHere's the code I got to work. Basically I reversed the item first, then figured out whether its length was even or odd. I returned the appropriate value with the if statement.
def first_4(item):
return item[:4]
def first_and_last_4(item):
return (item[:4] + item[-4:])
def odds(item):
return item[1::2]
def reverse_evens(item):
reverse_item = item[-1::-1]
if len(reverse_item) %2 == 0:
return reverse_item[1::2]
else:
return reverse_item[::2]
Camilla Bendetti
Python Web Development Techdegree Student 892 PointsI am still confused about doing it in two parts? Why doesnt return items[::-2] work on its own? Aryan Monga can you explain what you meant by "if len(a) % 2 == 0: return Figure it out else: return Figure it out"
Aryan Monga
4,061 PointsSure!! " if len(a) % 2 == 0: return a[-2 ::-2] else: return a[-1 ::-2] " This code checks whether the variable a has even total numbers or odd total numbers. If it has even numbers then it will return a[-2 ::-2] otherwise it will return a[-1 :: -2]. It's that simple! ;)
Christopher Shaw
Python Web Development Techdegree Graduate 58,248 PointsI agree with Aryan Monga , I would suggest doing in two steps, first get the evens in a new list, then reverse the new list.
Aryan Monga
4,061 PointsYeah!
Aryan Monga
4,061 PointsAryan Monga
4,061 PointsHello! Albert Tomasura. You need to return the reverse list with all odd indexes. You just typed the code of bringing out random numbers. I'm sorry if you do not understand. But, you need to check these first:
Check if the list has even or odd total numbers using an if statement and using the len function
If they have even numbers then return the code.
If they have odd numbers then return different codes.
'''python if len(a) % 2 == 0: return Figure it out else: return Figure it out ''' If you need any help or you are still confused. Then let me know. I will give you the code!