Dear Splus users,
I am dealing with a very long time series of daily data (more than 200 years).
The data frame where data are stored has been imported from Microsoft Excel;
the date is stored in the first column (of mode numeric) in the form d/m/yyyy
(for example 1/4/1780 or 15/11/1775). Some days might be missing.
I need to group data in various ways, for example by years or by months (all
the Januaries, …).
How can I do? Would it be possible to control the first column directly?
( I tried to create a new column with “dates” or “seq.dates”, but I am
not sure this is the best way of proceeding, also because it would be
impossible to manage the missing years).
Thank you for your attention and your help
Stefano
|