[R] Simple vector question.
rkevinburton at charter.net
rkevinburton at charter.net
Sat Jul 26 06:06:23 CEST 2008
I have some data that I read in via read.csv:
sales2007 <- read.csv("Total2007.dat", header=TRUE)
The data looks like:
> sales2007[1:605,]
Year DayOfYear Sku Quantity CatId Category SubCategory
1 2007 1 100091 1 10862 HOLIDAY Christmas
2 2007 1 100138 1 11160 PET COSTUMES Famous (Licensed)
3 2007 1 100194 1 10749 HATS, WIGS & MASKS Wigs - Women's
4 2007 1 100432 1 10865 HOLIDAY Easter
5 2007 1 100911 1 10120 MEN Superheroes Men
. . . .
600 2007 2 139002 1 10413 GIRLS Historical Girls
601 2007 2 138959 1 10322 BOYS TV & Movies Boys
602 2007 2 139005 1 10334 BOYS Toddlers Boys
603 2007 2 139052 1 10517 PLUS Plus Men
604 2007 2 138906 1 10322 BOYS TV & Movies Boys
605 2007 2 138860 1 0 (Unknown) (Unknown)
>
The DayOfYear goes from 1:365. I would like to form a vector from this data where the length of the vector is 365 and the value at each index coeresponds to the sum of the Quantity column where DayOfYear equals the index. For example if I was to use just the sample above this new vactor call it 'DayOfYearSales' would be:
DayOfYearSales[1] = 5
DayOfYearSales[2] = 6
Since in the snippet above only DayOfYear = 1:2 is shown. I want to continue the sum for the whole data frame. I am sure this is fairly easy. I just cannot find out how to do it. Once I figure this out it would be relatively straightforward to apply the same principle to columns of like Category, SKU, or SubCategory.
Something like:
table(Category)
would give me the number of entires for each unique value but I want the Quantity column used in this tabulation kind of like a frequency.
Thank you.
Kevin
More information about the R-help
mailing list