So, I have a dataset (usage) that is like the following, in R:
Item Bike Usage
item1 bike1 1
item2 bike1 2
item1 bike2 1
item3 bike2 2
And I wanted to convert on a matrix with the usage. I created a matrix where my header is the bikes (bike 1, bike2), and the row names is (item 1, item 2, item 3), and filled with NA and now I want to fill it the usage, such as:
bike1 bike2
item 1 1 1
item 2 1 0
item 3 0 1
I created the following loop:
for (i in 1:nrow(usage)) {
item<-usage[i,1]
bike<-usage[i,2]
matriz[item,bike]<-usage[i,3]
matriz[is.na(matriz)]<-0
}
But I get this error:
Error in `[<-`(`*tmp*`, item, bike, value = list(Usage = 6)) :
invalid subscript type 'list'
Maybe you can try xtabs if you need table
res_tb <- xtabs(Usage~.,df)
such that
> res_tb
Bike
Item bike1 bike2
item1 1 1
item2 2 0
item3 0 2
DATA
df <- structure(list(Item = c("item1", "item2", "item1", "item3"),
Bike = c("bike1", "bike1", "bike2", "bike2"), Usage = c(1L,
2L, 1L, 2L)), class = "data.frame", row.names = c(NA, -4L
))
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