[R] Extracting portions of one vector to create others

[Jeffrey Dick]

Hi Paul,

Here's a way that creates new vectors as elements of a list.

Beth <- list(
 CLASS = c(1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
   2, 2, 2, 2, 2, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4,
4, 4, 4, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7,
   7, 7, 7, 7, 7, 7, 7, 7, 7, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 1
 )
)

classes <- unique(Beth$CLASS)

# Loop over `classes` to operate on a single `class` in each iteration
result <- lapply(classes, function(class) {
  # Create a vector with 1 if Beth$CLASS is in class, 0 if not
  as.numeric(Beth$CLASS == class)
})

names(result) <- paste0("CLASS", classes)

with the result:

> result
$CLASS1
[1] 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 0
0
[83] 0 0 0 0 0 0 0 0 0 0 0 0 0 1

$CLASS2
[1] 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 1 1 1 1 1 1 1 1 1 1 1
1 1 1 1 1 1 1 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 0
0
[83] 0 0 0 0 0 0 0 0 0 0 0 0 0 0

[list truncated ...]

Regards,
Jeff

On Tue, Sep 2, 2025 at 2:44 PM Paul Zachos <paz using acase.org> wrote:
>
> Dear Colleagues,
>
> I have a vector which indicates membership of subjects in one of 5 Classes
>
> Beth$CLASS
>  [1] 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2
> [37] 2 2 2 2 2 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 7 7 7 7 7 7 7 7 7 7 7
> [73] 7 7 7 7 7 7 7 7 7 9 9 9 9 9 9 9 9 9 9 9 9 9 9 1
>
> For purposes of an analysis (using linear models based on Ward and Jennings) I would like to create 5 new vectors
>
> The values in vector CLASS1 will be ‘1’ if the corresponding value in Beth$CLASS is equal to ‘1’; ‘0’ otherwise
>
> The values in vector CLASS2 will be ‘1’ if the corresponding value in Beth$CLASS is equal to ‘2’; ‘0’ otherwise
>
> The values in vector CLASS4 will be ‘1’ if the corresponding value in Beth$CLASS is equal to ‘4’; ‘0’ otherwise
>
> The values in vector CLASS7 will be ‘1’ if the corresponding value in Beth$CLASS is equal to ‘7’; ‘0’ otherwise
>
> The values in vector CLASS9 will be ‘1’ if the corresponding value in Beth$CLASS is equal to ‘9’; ‘0’ otherwise
>
> How would I go about this using R
>
> Thank you
> _________________
> Paul Zachos, PhD
> Director, Research and Evaluation
> Association for the Cooperative Advancement of Science and Education (ACASE)
> 110 Spring Street  Saratoga Springs, NY 12866  |
> paz using acase.org  |  www.acase.org
>
>
>
>
>
>         [[alternative HTML version deleted]]
>
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