Question

I need to break down a date in python into: year, month, day and time(hour).

I have a list of objects, each object has a date property:

startDate=db.DateTimeProperty(auto_now_add=True)

The date property containts, the year, the month, the day and the time all in one.

I wish to create a new nested list(dictionary) where:

Outer list- is a list of years(that are present in at least one of the input dates) -> inside each year a list of months(that are present during that year in at least one of the input dates)-> inside this days(same as with months – days present in the input list) -> Inside that a list of times(hours)… each our pointing to it’s respective object.

I hope this is easily understood.

If I get the list bellow as input:

{obj1 -> (2000 Dec 18 9:00AM), obj2 -> (2000 Dec 19 1:00PM)}

It will clamp them together so I’ll have

(2000) -> (Dec) -> {(18) -> (9:00AM) -> obj1 ,(19) -> (1:00PM) -> obj2}

I hope this makes sense..

Basically I have a lot of events with dates and I want to list them like this:

Year ->
Month(s) of interest->
Day(s) of interest->
(event times)
.
.
.

Another Year ->
Relevant Month(s) ->
Relevant Day(s) ->
(event times)
.
.
.

Instead of:

(Event1 : complete date & time) , (Event2 : complete date & time) , (event3 : complete date & time)

Thanks

Answer 1

class a: ## Using this class just to explain
    def __init__(self,y,m,d,t):
        self.y=y
        self.m=m
        self.d=d
        self.t=t


o1 = a(2000,12,18,9) ## Just assuming integers here. you can choose immutable objects here
o2 = a(2000,12,19,13)
o3 = a(2001,11,18,9)
o4 = a(2000,11,18,6)
o5 = a(2000,12,6,7)

l=[o1,o2,o3,o4,o5]


d={}

for o in l:
    if o.y not in d:
        d[o.y] = {}
    # print d
    if o.m not in d[o.y]:
        d[o.y][o.m]={}
    if o.d not in d[o.y][o.m]:
        d[o.y][o.m][o.d]={}
    if o.t not in d[o.y][o.m][o.d]:
        d[o.y][o.m][o.d][o.t]=o

You can try producing a better formatted output:

for k,v in d.items():
    for j,h in v.items():
        print k,j,h

I get output as:

2000 11 {18: {6: <__main__.a instance at 0x0232E9E0>}}
2000 12 {18: {9: <__main__.a instance at 0x0232E940>}, 19: {13: <__main__.a instance at 0x0232E990>}, 6: {7: <__main__.a instance at 0x0232EA08>}}
2001 11 {18: {9: <__main__.a instance at 0x0232E9B8>}}