Computation by rows
Compute on a data frame a row-at-a-time. This is most useful when a vectorised function doesn't exist. Only mutate and summarise are supported so far.
rowwise_mutate(.data, ...) rowwise_summarise(.data, ...)
.data |
A data.table |
... |
Name-value pairs of expressions |
A data.table
# without rowwise
df <- data.table(x = 1:2, y = 3:4, z = 4:5)
df %>% mutate(m = mean(c(x, y, z)))
# with rowwise
df <- data.table(x = 1:2, y = 3:4, z = 4:5)
df %>% rowwise_mutate(m = mean(c(x, y, z)))
# # rowwise is also useful when doing simulations
params = fread(" sim n mean sd
1 1 1 1
2 2 2 4
3 3 -1 2")
params %>%
rowwise_summarise(sim,z = rnorm(n,mean,sd))Please choose more modern alternatives, such as Google Chrome or Mozilla Firefox.