Dear R experts,
I have a problem in modifying one column of a dataframe with a datatime
format using a datetime operator.
Here is my dataframe A:
DATACONT PROVINCIA VALORE
1 2007-12-31 MI 1
2 2007-12-31 PV 2
3 2007-12-31 NA 3
4 2007-12-31 MI 4
5 2007-12-31 RM 5
6 2007-12-31 RM 6
7 2007-12-31 MI 7
8 2008-12-31 MI 11
9 2008-12-31 PV 12
10 2008-12-31 NA 13
11 2008-12-31 MI 14
12 2008-12-31 RM 15
13 2008-12-31 RM 16
14 2008-12-31 MI 17
15 2006-12-31 MI -9
16 2006-12-31 PV -8
17 2006-12-31 NA -7
18 2006-12-31 MI -6
19 2006-12-31 RM -5
20 2006-12-31 RM -4
21 2006-12-31 MI -3
Suppose I want to shift all dates by 1 year, obtaining the following
dataframe B:
DATACONT PROVINCIA VALORE
1 2008-12-31 MI 1
2 2008-12-31 PV 2
3 2008-12-31 NA 3
4 2008-12-31 MI 4
5 2008-12-31 RM 5
6 2008-12-31 RM 6
7 2008-12-31 MI 7
8 2009-12-31 MI 11
9 2009-12-31 PV 12
10 2009-12-31 NA 13
11 2009-12-31 MI 14
12 2009-12-31 RM 15
13 2009-12-31 RM 16
14 2009-12-31 MI 17
15 2007-12-31 MI -9
16 2007-12-31 PV -8
17 2007-12-31 NA -7
18 2007-12-31 MI -6
19 2007-12-31 RM -5
20 2007-12-31 RM -4
21 2007-12-31 MI -3
I tried with seq.Date:
seq.Date(a$"DATA",by="1 month",len=2)[2]
but it works only for single values (the "from" must have length=1).
Any hints ?
Thank you in advance
Angelo Linardi
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