Displaying 2 results from an estimated 2 matches for "observation_d".
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observationid
2009 Apr 28
3
help working with date values
My data contains a variable "observation_date" and it contains values as:
1985-09-02
1985-09-15
1985-07-31
1985-09-02
I need to process data annually rather than daily, therefore I'm trying to
1) either extract the first 4 digits from this field and use them as a new
variable "year" or 2) keep the variable as it is a...
2009 Jan 27
1
Creating list or numeric vectors out of selected columns of row oriented data
...not change and the start_date does
not change, but the obeservation_date and the three different
observations change between rows. (There is one row for each day for
each subject over a three year period although some entered the study
late):
'subject_id', 'start_date','observation_date','weight_obs',
'activity_obs','calories_obs'
1,'1/1/2005','1/1/2005',3.26,'a',93
1,'1/1/2005','1/2/2005',3.22,'o',85
1,'1/1/2005','1/3/2005',3.28,'o',91
...
1,'1/1/2005','12/31/2008&...