I have a data frame where I want to create a new column in which to assign the same ID every 30 rows.
My data frame is from an experiment and I wish to create a new "bloc" column, so that every 30 rows it increments by 1
example:
col1 : response latency = 1,0002, 1.2566, ...30times, 1.5422, ...
col2 : difficulty = easy, hard, intermediate, ...
col3 : ID = 1, 2, 3, ...30times, 31, 32, ...
And I want a new column
new col : bloc = 1, 1, ...30times, 2, 2, ...30times, 3, 3, ...
Using 5 as an example, but this of course works the same for 30
df <- data.frame(rownum = 1:23)
bloc_len <- 5
df$bloc <-
rep(seq(1, 1 + nrow(df) %/% bloc_len), each = bloc_len, length.out = nrow(df))
df
# rownum bloc
# 1 1 1
# 2 2 1
# 3 3 1
# 4 4 1
# 5 5 1
# 6 6 2
# 7 7 2
# 8 8 2
# 9 9 2
# 10 10 2
# 11 11 3
# 12 12 3
# 13 13 3
# 14 14 3
# 15 15 3
# 16 16 4
# 17 17 4
# 18 18 4
# 19 19 4
# 20 20 4
# 21 21 5
# 22 22 5
# 23 23 5
You could also use %/% (same output)
df$bloc <-
1 + seq(0, nrow(df) - 1) %/% bloc_len
You can use rep(x, times) function to create the bloc you wished.
See the example above
set.seed(12345)
Create a random data set
data <- data.frame(
response_latency = abs(rnorm(90, 2, 1)),
difficulty = sample(c("easy", "hard", "intermediate"), 90, replace = TRUE),
ID = 1:90
)
head(data, n = 35)
response_latency difficulty ID bloc
1 1.8890497 intermediate 1 1
2 2.9996586 intermediate 2 1
3 3.0255886 hard 3 1
4 0.3949156 hard 4 1
5 2.0027199 easy 5 1
6 2.9580737 hard 6 1
7 1.3337903 intermediate 7 1
8 1.4844084 hard 8 1
9 1.3941750 hard 9 1
10 1.6923244 intermediate 10 1
11 1.8186642 easy 11 1
12 0.9167691 easy 12 1
13 2.5987185 easy 13 1
14 1.8345693 intermediate 14 1
15 0.9177725 hard 15 1
16 2.3445309 easy 16 1
17 2.5187724 hard 17 1
18 1.2220053 hard 18 1
19 2.1636086 hard 19 1
20 0.7847963 hard 20 1
21 1.3785363 hard 21 1
22 2.9451529 intermediate 22 1
23 2.3722482 intermediate 23 1
24 2.1812877 intermediate 24 1
25 0.1383615 easy 25 1
26 1.3996498 easy 26 1
27 3.7593749 hard 27 1
28 2.0056114 hard 28 1
29 3.2195714 hard 29 1
30 2.1481248 easy 30 1
31 3.2546741 intermediate 31 2
32 2.4221608 hard 32 2
33 2.0465687 intermediate 33 2
34 1.7649423 easy 34 2
35 1.7338255 hard 35 2
Here, to add the bloc column in your dataset, you can use the following code:
bloc <- c(rep(x = 1, times = 30), rep(x = 2, times = 30), rep(x = 3, times = 30))
data$bloc <- bloc
head(data,n=35)
The new dataset will be as follow.
response_latency difficulty ID bloc
1 1.8890497 intermediate 1 1
2 2.9996586 intermediate 2 1
3 3.0255886 hard 3 1
4 0.3949156 hard 4 1
5 2.0027199 easy 5 1
6 2.9580737 hard 6 1
7 1.3337903 intermediate 7 1
8 1.4844084 hard 8 1
9 1.3941750 hard 9 1
10 1.6923244 intermediate 10 1
11 1.8186642 easy 11 1
12 0.9167691 easy 12 1
13 2.5987185 easy 13 1
14 1.8345693 intermediate 14 1
15 0.9177725 hard 15 1
16 2.3445309 easy 16 1
17 2.5187724 hard 17 1
18 1.2220053 hard 18 1
19 2.1636086 hard 19 1
20 0.7847963 hard 20 1
21 1.3785363 hard 21 1
22 2.9451529 intermediate 22 1
23 2.3722482 intermediate 23 1
24 2.1812877 intermediate 24 1
25 0.1383615 easy 25 1
26 1.3996498 easy 26 1
27 3.7593749 hard 27 1
28 2.0056114 hard 28 1
29 3.2195714 hard 29 1
30 2.1481248 easy 30 1
31 3.2546741 intermediate 31 2
32 2.4221608 hard 32 2
33 2.0465687 intermediate 33 2
34 1.7649423 easy 34 2
35 1.7338255 hard 35 2