Assigning to a new list just the last object of another list - Python

Question

OK, in Python I have list:

flowers = ["rose", "bougainvillea", "yucca", "marigold", "daylilly", "lilley of the valley"]

Now, I want to assign just the last object of list flowers to a new list called poisonous.

I tried:

poisonous=flowers[-1]

However this statement makes poisonous a string instead of a list.

score 3 · Answer 1 · answered Sep 15 '13 at 02:59

>>> poisonous=[flowers[-1],] #take the last element and put it in a list
>>> poisonous
['lilley of the valley']
>>> poisonous=flowers[-1] #take the last element, which is a string
>>> poisonous
'lilley of the valley'
>>> poisonous=flowers[-1:] #take a slice of the original list. The slice is also a list.
>>> poisonous
['lilley of the valley']

karthikr · Accepted Answer · 2013-09-15T03:00:43.383

2

Try this instead

poisonous=flowers[-1:]

Demo:

>>> flowers = ["rose", "bougainvillea", "yucca", "marigold", "daylilly", "lilley of the valley"]
>>> 
>>> flowers[-1:]
['lilley of the valley']

Your issue was, you were indexing, which returns an object. Whereas, slicing would return a list.

edited Sep 15 '13 at 03:00

answered Sep 15 '13 at 02:55

karthikr

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Since it is not obvious how this works if you haven't seen it before: http://stackoverflow.com/a/509295 – flornquake Sep 15 '13 at 02:58
Looks good. The colon is what is required to make it into a list then? – Terry Schmidt Sep 15 '13 at 02:59
@user2461994 That is right. You needed a slice instead of the indexing . – karthikr Sep 15 '13 at 02:59

score 1 · Answer 3 · answered Sep 15 '13 at 02:59

1

You can wrap the object to be assigned in square bracket to make it a list assignment.

poisonous = [flowers[-1]]

answered Sep 15 '13 at 02:59

edi_allen

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7stud · Answer 4 · 2013-09-15T04:34:24.400

0

And, probably more useful:

flowers = [
    "rose", 
    "bougainvillea", 
    "poison oak",
    "yucca", 
    "marigold", 
    "daylily", 
    "lily of the valley",
]

snakes = [
    "king",
    "rattler",
]

poisonous = []

poisonous.append(flowers[-1])
poisonous.append(snakes[-1])

print poisonous

--output:--
['lily of the valley', 'rattler']

edited Sep 15 '13 at 04:34

answered Sep 15 '13 at 04:27

7stud

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Assigning to a new list just the last object of another list - Python

4 Answers4