dictionary and stack in python problem

Question

I have made a dictionary and I put the keys of the dict in a list. My list contains elements like this:

s =  [((5, 4), 'South', 1), ((4, 5), 'West', 1)]

I made a dict from this:

child = dict((t[0], t[1]) for t in s)

keys = child.keys()
print keys

The output is : [(4, 5), (5, 4)]

Now I need to put (4,5) and (5,4) into stack. What should I do?

I tried, but when I do pop from the stack it is giving me the 2 elements together. like stack.pop() - output is : [(4, 5), (5, 4)]. I want to pop one by one... (4,5) and then (5,4)

could you clarify? what are you doing, what is it doing that you think is wrong, and what would you like it to do? — eruciform
– eruciform, Commented Jul 17, 2010 at 22:35
This question needs a lot of clarification. I wish that SO had a template for asking questions, with sections like "What I tried" and "What it should look like". — Jesse Dhillon
– Jesse Dhillon, Commented Jul 17, 2010 at 22:52

Mark Byers · Accepted Answer · 2010-07-17 22:47:05Z

2

You can use a list as a stack:

stack = list(child.keys())
print stack.pop()
print stack.pop()

Result:

(5, 4)
(4, 5)

Important note: the keys of a dictionary are not ordered so if you want the items in a specific order you need to handle that yourself. For example if you want them in normal sorted order you could use sorted. If you want them to pop off in reverse order from the order they were in s you could skip the conversion to a dictionary and just go straight from s to your stack:

stack = [x[0] for x in s]
print stack.pop()
print stack.pop()

Result:

(4, 5)
(5, 4)

answered Jul 17, 2010 at 22:47

Mark Byers

844k202 gold badges1.6k silver badges1.5k bronze badges

Sign up to request clarification or add additional context in comments.

Comments

eruciform · Accepted Answer · 2010-07-17 22:46:02Z

0

I think user wants this:

# python
> stack = [(4, 5), (5, 4)]
> stack.pop(0)
(4,5)
> stack.pop(0)
(5,4)

Just a reminder, though, this is not a proper stack. This is a proper stack:

# python
> stack=[]
> stack.append( (4,5) )    
> stack.append( (5,4) )
> stack.pop()
(5,4)
> stack.pop()
(4,5)

answered Jul 17, 2010 at 22:46

eruciform

7,7561 gold badge38 silver badges48 bronze badges

Comments

Quonux · Accepted Answer · 2010-07-17 22:43:25Z

0

use

element = stack[0]
if len(stack) > 0:
   stack = stack[1:]

print element

but it is not that kind of a stack :/

answered Jul 17, 2010 at 22:43

Quonux

2,9911 gold badge25 silver badges33 bronze badges

2 Comments

eruciform Over a year ago

@shilpa, pushing and popping on a list is a proper stack. push puts on the end, pop removes from the end.

Quonux Over a year ago

it is basicaly the same, you can "wrap" this in a own class and call it stack (with your function names and so on)

Collectives™ on Stack Overflow

dictionary and stack in python problem

3 Answers 3

Comments

Comments

2 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

3 Answers 3

Comments

Comments

2 Comments

Your Answer

Sign up or log in

Post as a guest

Related