R help - Sep 2009 - How to sum and group data by DATE in data frame

Dear all,

Lets say I have a data frame as follows:

> Date <- as.Date(c('2006-08-23', '2006-08-30',
'2006-09-06', '2006-09-13', '2006-09-20'))
> Income <- c(73.79, 72.46, 76.32, 72.43, 72.62)
> data.frame(Date, Income)
        Date Income
1 2006-08-23  73.79
2 2006-08-30  72.46
3 2006-09-06  76.32
4 2006-09-13  72.43
5 2006-09-20  72.62
>
is there a way to group the data by month (summing the values in each
month), i.e.

Date       Income
2006-08  146.25
2006-09  221.37

Thanks in advance,
C.C.

Hi Clair,
try to use this code

aggregate(toto$Income,by=list((substr(toto$Date,1,7))),sum)

Regards
mohamed

clair.crossupton at googlemail.com a ?crit :
> Dear all,
>
> Lets say I have a data frame as follows:
>
>
>   
>> Date <- as.Date(c('2006-08-23', '2006-08-30',
'2006-09-06', '2006-09-13', '2006-09-20'))
>> Income <- c(73.79, 72.46, 76.32, 72.43, 72.62)
>> data.frame(Date, Income)
>>     
>         Date Income
> 1 2006-08-23  73.79
> 2 2006-08-30  72.46
> 3 2006-09-06  76.32
> 4 2006-09-13  72.43
> 5 2006-09-20  72.62
>   
>
> is there a way to group the data by month (summing the values in each
> month), i.e.
>
> Date       Income
> 2006-08  146.25
> 2006-09  221.37
>
> Thanks in advance,
> C.C.
>
> ______________________________________________
> R-help at r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide
http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
>
>   

-- 
Mohamed Lajnef
INSERM Unit? 955. 
40 rue de Mesly. 94000 Cr?teil.
Courriel : Mohamed.lajnef at inserm.fr 
tel. : 01 49 81 31 31 (poste 18470)
Sec : 01 49 81 32 90
fax : 01 49 81 30 99

Try this:

rowsum(Income, format(Date, '%m-%Y'))

or

tapply(Income, format(Date, '%m-%Y'), sum)

On Wed, Sep 9, 2009 at 7:51 AM, clair.crossupton@googlemail.com <
clair.crossupton@googlemail.com> wrote:
> Dear all,
>
> Lets say I have a data frame as follows:
>
>
> > Date <- as.Date(c('2006-08-23', '2006-08-30',
'2006-09-06', '2006-09-13',
> '2006-09-20'))
> > Income <- c(73.79, 72.46, 76.32, 72.43, 72.62)
> > data.frame(Date, Income)
>        Date Income
> 1 2006-08-23  73.79
> 2 2006-08-30  72.46
> 3 2006-09-06  76.32
> 4 2006-09-13  72.43
> 5 2006-09-20  72.62
> >
>
> is there a way to group the data by month (summing the values in each
> month), i.e.
>
> Date       Income
> 2006-08  146.25
> 2006-09  221.37
>
> Thanks in advance,
> C.C.
>
> ______________________________________________
> R-help@r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide
> http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
>


-- 
Henrique Dallazuanna
Curitiba-Paraná-Brasil
25° 25' 40" S 49° 16' 22" O

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