CODEWITHSUNDEEP
rdplyr
Mark Hamlin
Mark Hamlin

Reputation: 348

produce a non deterministic result for each tibble row with mutate

tibble(x=c(1,2,3)) %>%
  mutate(y = runif(1))

This results in the same quantity assigned to each Y. Why is this and how can i ensure the function I supply is called once for each row, regardless of the value and type of the arguments?

Upvotes: 2

Views: 36

Answers (1)

lroha
lroha

Reputation: 34376

The n argument of runif() takes either an integer or a vector of values. If a vector is used its length is taken to be the number required. This means you can pass it a vector of any class and it will return a result of equal length.

library(dplyr)

tibble(x=c(1,2,3)) %>%
  mutate(y = runif(x))

# A tibble: 3 x 2
      x     y
  <dbl> <dbl>
1     1 0.445
2     2 0.778
3     3 0.632

Upvotes: 3

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