# [R] Occurrence by season

Eric Berger er|cjberger @end|ng |rom gm@||@com
Wed Apr 21 10:47:55 CEST 2021

```Hi Ani,
Before the for loops add the following line

when[,-1] <- when[,-1]%%12 + 1

This changes the month numbering so that Dec becomes 1, Jan becomes 2, etc
Then your for loop does what you want.

HTH,
Eric

On Wed, Apr 21, 2021 at 11:09 AM ani jaya <gaaauul using gmail.com> wrote:

> Dear r community,
>
> I have a data frame that shows the month of occurrence of the maximum
> value on let say 10 stations in 30 years.  I want to make percentages
> based on seasons (DJF, MAM, JJA, and SON). I can do that by the code
> below but only when we put season by JFM, AMJ, ...(or 123; 456;
> 789;..).
> I believe it is not that hard to put 12 in front of 1 but my mind stuck.
>
> If someone can help me, I would be appreciated.
>
> Thank you in advance
>
> Ani
>
>
> freqw<-matrix(NA, 4,10)
> for(j in 1:4){
>   for(i in 1:10){
>       freqw[j,i]<-sum(table(when[i+1])[(j*3-2):(j*3)],na.rm=T)
>   }
> }
> freqw<-freqw/30*100
>
>
> > dput(when)
> structure(list(Group.1 = structure(1:30, .Label = c("1985", "1986",
> "1987", "1988", "1989", "1990", "1991", "1992", "1993", "1994",
> "1995", "1996", "1997", "1998", "1999", "2000", "2001", "2002",
> "2003", "2004", "2005", "2006", "2007", "2008", "2009", "2010",
> "2011", "2012", "2013", "2014"), class = "factor"), V1 = c(8L,
> 1L, 1L, 12L, 12L, 1L, 4L, 1L, 2L, 3L, 7L, 4L, 1L, 6L, 2L, 2L,
> 11L, 4L, 2L, 2L, 12L, 6L, 2L, 2L, 6L, 3L, 6L, 4L, 7L, 1L), V2 = c(1L,
> 1L, 1L, 1L, 12L, 12L, 4L, 1L, 2L, 2L, 4L, 1L, 11L, 1L, 1L, 3L,
> 3L, 1L, 12L, 2L, 5L, 2L, 12L, 2L, 1L, 5L, 10L, 4L, 12L, 1L),
>     V3 = c(4L, 1L, 12L, 12L, 2L, 4L, 1L, 5L, 1L, 1L, 2L, 2L,
>     1L, 1L, 2L, 2L, 4L, 1L, 2L, 12L, 3L, 2L, 12L, 4L, 6L, 4L,
>     2L, 3L, 5L, 1L), V4 = c(1L, 12L, 12L, 3L, 2L, 12L, 7L, 2L,
>     12L, 1L, 12L, 2L, 1L, 12L, 1L, 10L, 7L, 1L, 1L, 3L, 10L,
>     12L, 12L, 12L, 5L, 12L, 3L, 2L, 12L, 1L), V5 = c(1L, 12L,
>     12L, 3L, 2L, 12L, 7L, 2L, 12L, 3L, 4L, 12L, 5L, 2L, 1L, 1L,
>     2L, 5L, 2L, 2L, 3L, 2L, 10L, 3L, 1L, 1L, 4L, 1L, 4L, 6L),
>     V6 = c(12L, 1L, 12L, 2L, 1L, 12L, 3L, 1L, 4L, 12L, 6L, 12L,
>     1L, 7L, 2L, 2L, 1L, 1L, 12L, 12L, 12L, 3L, 12L, 2L, 1L, 9L,
>     12L, 1L, 4L, 12L), V7 = c(5L, 2L, 6L, 12L, 3L, 4L, 12L, 12L,
>     6L, 2L, 11L, 12L, 2L, 5L, 11L, 4L, 3L, 4L, 1L, 12L, 10L,
>     3L, 10L, 3L, 3L, 9L, 1L, 3L, 12L, 11L), V8 = c(4L, 5L, 5L,
>     8L, 7L, 12L, 1L, 3L, 2L, 5L, 2L, 4L, 1L, 4L, 1L, 6L, 6L,
>     2L, 3L, 5L, 4L, 1L, 3L, 12L, 4L, 12L, 12L, 3L, 6L, 7L), V9 = c(3L,
>     2L, 3L, 11L, 7L, 2L, 4L, 4L, 5L, 6L, 6L, 3L, 4L, 6L, 1L,
>     9L, 9L, 12L, 3L, 12L, 5L, 6L, 3L, 7L, 4L, 8L, 2L, 2L, 6L,
>     6L), V10 = c(5L, 10L, 3L, 6L, 6L, 5L, 5L, 6L, 5L, 6L, 12L,
>     6L, 7L, 2L, 1L, 6L, 4L, 5L, 4L, 2L, 7L, 6L, 7L, 7L, 2L, 7L,
>     3L, 6L, 7L, 6L)), row.names = c(NA, -30L), class = "data.frame")
>
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