[ideas] tar_reduce - ability to aggregate/summarize multiple targets

[collinschwantes]

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Description

This idea is similar to whats discussed in #987. Lets say I have a set of targets that I need to combine into a single data frame. They all start with "xyz_". Ideally, I could run something like tar_reduce(name = combined_df, values = starts_with("xyz_"), command = rbind) which would give me my desired data frame. Any ideas on how to do this?

The example below seems to work but maybe there is a better solution?

test <- tar_plan(

    tar_target(mtcars1, mtcars),
    tar_target(mtcars2, mtcars),
    tar_target(mtcars3, mtcars),
    tar_target(iris1, iris)

)

list(
    test,
    tar_combine(combined, tar_select_targets(test, starts_with("mtcars")))
)

[wlandau]

tar_combine() is the canonical "reduce" solution in the targets ecosystem. At a glance, your code sketch looks right.