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Python Python Collections (Retired) Slices Slice Functions

Ben Swift
Ben Swift
6,201 Points
Posted by Ben Swift
Ben Swift
6,201 Points

Confused with first_and_last_4

Make a function name first_and_last_4 that accepts an iterable and returns the first 4 and last 4 items in the iterable.

slices.py 
def first_4(iterable):
  return iterable[0:4]

def odds(iterable2):
  return iterable2[1::2]

def first_and_last_4(iterable4):
  return iterable4[0:4] + iterable[:-4]

4 Answers

Safery Hossain
Safery Hossain
3,484 Points

You made a mistake on your first_and_last_4(). First of all, you called non global variable iterable, so python thinks it is not defined. Second mistake is your sliced it like this '[:-4]'. Python interprets this as [Begin from index 0: End at the 4'th index from last].

you can use the below code:

To get the last 4 item, i looked for the length and minus 4.

def first_and_last_4(iterable4):
  '''(str) -> str
  returns the item from the first 4 and last 4 index.
  '''
  return iterable4[:4] + iterable4[len(iterable4)-4:]
Ben Swift
Ben Swift
6,201 Points
Ben Swift
Ben Swift
6,201 Points

Thank you so much!

Milos Town
seal-mask
.a{fill-rule:evenodd;}techdegree
Milos Town
Python Web Development Techdegree Student 2,633 Points
Milos Town
.a{fill-rule:evenodd;}techdegree
Milos Town
Python Web Development Techdegree Student 2,633 Points

Ben, You were almost there! Make sure you use the same parameter. 

def first_and_last_4(iterable4):
  return iterable4[0:4] + iterable4[-4:]
Sylvester Zharima
Sylvester Zharima
3,816 Points
Sylvester Zharima
Sylvester Zharima
3,816 Points

def first_4(itera): return itera[:4]

def first_and_last_4(n): return n[:4] + n[-4:]

def odds(index): return index[1::2]

def reverse_evens(index): return index[::22][::-1]

just try this

Amanda Perez
PLUS
Amanda Perez
Courses Plus Student 2,056 Points
Amanda Perez
Amanda Perez
Courses Plus Student 2,056 Points

I have tried all answers including my own and all I get is couldn't find 'first_4' :(

Tapiwanashe Taurayi
Tapiwanashe Taurayi
15,889 Points
Tapiwanashe Taurayi
Tapiwanashe Taurayi
15,889 Points

def first_4(itera): return itera[:4] def first_and_last_4(n): return n[:4] + n[-4:] def odds(index): return index[1::2] def reverse_evens(index): return index[::22][::-1]