R: Compare elements from a column based upon other column conditions?-CodePudding

I would like to create a new df, based upon whether the second or third condition's for each subject are greater than the first condition.

Example df:

df1 <- data.frame(subject = rep(1:5, 3),
                  condition = rep(c("first", "second", "third"), each = 5),
                  values = c(.4, .4, .4, .4, .4, .6, .6, .6, .6, .4, .6, .6, .6, .4, .4))
> df1
   subject condition values
1        1     first    0.4
2        2     first    0.4
3        3     first    0.4
4        4     first    0.4
5        5     first    0.4
6        1    second    0.6
7        2    second    0.6
8        3    second    0.6
9        4    second    0.6
10       5    second    0.4
11       1     third    0.6
12       2     third    0.6
13       3     third    0.6
14       4     third    0.4
15       5     third    0.4

The resulting df would be this:

> df2
   subject condition values
1        1     first    0.4
2        2     first    0.4
3        3     first    0.4
4        4     first    0.4
6        1    second    0.6
7        2    second    0.6
8        3    second    0.6
9        4    second    0.6
11       1     third    0.6
12       2     third    0.6
13       3     third    0.6
14       4     third    0.4

Here, subject #5 does not meet the criteria. This is because only subject #5's values are not greater than the first condition in either the second or third condition.

Thanks.

CodePudding user response：

We may group by 'subject' and filter if any of the second or third 'values' are greater than 'first'

library(dplyr)
df1 %>% 
 group_by(subject) %>%
 filter(any(values[2:3] > first(values))) %>%
 ungroup

-output

# A tibble: 12 × 3
   subject condition values
     <int> <chr>      <dbl>
 1       1 first        0.4
 2       2 first        0.4
 3       3 first        0.4
 4       4 first        0.4
 5       1 second       0.6
 6       2 second       0.6
 7       3 second       0.6
 8       4 second       0.6
 9       1 third        0.6
10       2 third        0.6
11       3 third        0.6
12       4 third        0.4

CodePudding user response：

Using ave.

df1[with(df1, ave(values, subject, FUN=\(x) any(x[2:3] > x[1])) == 1), ]
#    subject condition values
# 1        1     first    0.4
# 2        2     first    0.4
# 3        3     first    0.4
# 4        4     first    0.4
# 6        1    second    0.6
# 7        2    second    0.6
# 8        3    second    0.6
# 9        4    second    0.6
# 11       1     third    0.6
# 12       2     third    0.6
# 13       3     third    0.6
# 14       4     third    0.4