CODEWITHSUNDEEP
rrandomuniform-distribution
nba2020
nba2020

Reputation: 698

R row-wise runif() between 2 columns

I have the following data frame DF :

Min Max
10  20
14  34
9   29
... ...

and want to add a new column that samples a number between Min and Max of each row with uniform distribution. I've tried the below but give me the same number for all rows, meaning it's not sampling row by row as desired:

DF$random <- runif(1,min=DF$Min,max=DF$Max)

How may I achieve this?

Upvotes: 0

Views: 814

Answers (2)

ThomasIsCoding
ThomasIsCoding

Reputation: 101916

Here is a base R solution

  • just runif() (thanks to comments by @David Arenburg)
df$val <- with(df,runif(nrow(df),Min,Max))
  • using Vectorize()
f <- Vectorize(function(x,y) runif(1,min=x,max=y),vectorize.args = c("x","y"))
df$val <- with(df,f(Min,Max))

such that

> df
  Min Max      val
1  10  20 14.51209
2  14  34 29.85087
3   9  29 22.97049

DATA

df <- structure(list(Min = c(10L, 14L, 9L), Max = c(20L, 34L, 29L)), class = "data.frame", row.names = c(NA, 
-3L))

Upvotes: 1

Allan Cameron
Allan Cameron

Reputation: 174128

Try this:

library(dplyr)
DF <- data.frame(Min = c(10,14,9), Max= c(20,32,29))
DF %>% mutate(new_sample = mapply(function(x, y) runif(1, x, y), Min, Max))
#   Min Max new_sample
# 1   1  10   2.581535
# 2  11  20  13.287205
# 3  21  30  23.546859

Upvotes: 1

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