So we want to add person-level summaries of a variable to the right of a data-frame?
- Create some data
- The
dplyr
way
- The
data.table
way
- The base R way
ID
|
X
|
x
|
1
|
-0.5811347
|
0.2034073
|
1
|
-0.3858843
|
0.2034073
|
1
|
0.9627655
|
0.2034073
|
1
|
1.6026897
|
0.2034073
|
1
|
-0.5813995
|
0.2034073
|
2
|
0.6804060
|
-1.0253115
|
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