Convert frequency to raw data values R [duplicate]

Question

: ：

Repeat each row of data.frame the number of times specified in a column (9 answers)

Closed 2 hours ago .

Give a dataframe in R

structure(list(Feat1 = c("A", "B", "A", "B"), Time = c("Start", 
"Start", "Finish", "Finish"), Value = c("Value1", "Value2", "Value3", 
"Value2"), feat2 = c("Alpha", "Bravo", "Alpha", "Bravo"), Frequency = c(2L, 
4L, 5L, 3L)), class = "data.frame", row.names = c(NA, -4L))

I have both the frequencies and also features of a certain set of observations. I want all the frequencies to be converted to a number of rows equal to the frequency value while keeping the features.

As an example, the first row becomes these 2 rows because frequency was 2

Answer 1

Try uncount :

library(tidyr)
dat %>% 
  uncount(Frequency)

output:

   Feat1   Time  Value feat2
1      A  Start Value1 Alpha
2      A  Start Value1 Alpha
3      B  Start Value2 Bravo
4      B  Start Value2 Bravo
5      B  Start Value2 Bravo
6      B  Start Value2 Bravo
7      A Finish Value3 Alpha
8      A Finish Value3 Alpha
9      A Finish Value3 Alpha
10     A Finish Value3 Alpha
11     A Finish Value3 Alpha
12     B Finish Value2 Bravo
13     B Finish Value2 Bravo
14     B Finish Value2 Bravo

Answer 2

A base solution:

df[rep(seq_len(nrow(df)), df$Frequency), ]

where the rep part gives a repeated indices fro each row.

[1] 1 1 2 2 2 2 3 3 3 3 3 4 4 4