[R] Date extract Year

[Rolf Turner]

On 09/03/15 07:27, Steven Archambault wrote:

> My date column is the excel numeric date format. For instance, in
> excel, that first date is 11 September 2012.

And we were supposed to know that?  The level of obtuseness of people
who post to this list truly knows no lower bound.

Be that as it may, you could do:

o <- as.Date("2012/09/11")-41163
date1 <- as.Date(wells$Date,origin=o)

cheers,

Rolf Turner

>
> On Mar 8, 2015, at 10:41 AM, Frederic Ntirenganya <ntfredo at gmail.com> wrote:
>
>> Hi Steve,
>>
>> Can you please explain to us your date column? thanks.
>>
>> Regards,
>> Fredo.
>> On Mar 8, 2015 7:32 PM, "Steve Archambault" <archstevej at gmail.com> wrote:
>> Hi all,
>>
>> I am trying in vain to create a new object "Year" in my data frame from
>> existing Date data. I have tried many different approaches, but can't seem
>> to get it to work. Here is an example of some code I tried.
>>
>> date1<- as.Date(wells$Date,"%m/%d/%Y")
>> wells$year<-as.numeric(format(date1, "%Y"))
>>
>> I am starting with data that looks like this.
>>
>>          ID  Date DepthtoWater_bgs test test2
>> 1  BC-0004 41163           260.60    3     1
>> 2  BC-0004 41255           261.65    4     2
>> 3  BC-0003 41345           166.58    5     3
>> 4  BC-0002 41351           317.85    6     4
>> 5  BC-0004 41355           262.15    7     5
>> 6  BC-0003 41438           167.55    8     6
>> 7  BC-0004 41438           265.45    9     7
>> 8  BC-0002 41443           317.25   10     8
>> 9  BC-0002 41521           321.25   11     9
>> 10 BC-0003 41522           168.65   12    10
>> 11 BC-0004 41522           266.15   13    11
>> 12 BC-0003 41627           168.95   14    12
>> 13 BC-0004 41627           265.25   15    13
>> 14 BC-0002 41634           312.31   16    14
>> 15 BC-0003 41703           169.25   17    15
>> 16 BC-0004 41703           265.05   18    16
>> 17 BC-0002 41710           313.01   19    17
>> 18 BC-0003 41795           168.85   20    18
>> 19 BC-0004 41795           266.95   21    19
>> 20 BC-0002 41801           330.41   22    20
>> 21 BC-0003 41905           169.75   23    21
>> 22 BC-0004 41905           267.75   24    22
>> 23 BC-0002 41906           321.01   25    23
>>
>> Any help would be greatly appreciated!

-- 
Rolf Turner
Technical Editor ANZJS
Department of Statistics
University of Auckland
Phone: +64-9-373-7599 ext. 88276
Home phone: +64-9-480-4619