Find agent skills by outcome

- Factor indexing: `x[f]` uses integer codes of factor `f`

not its character labels. Use `x[as.character(f)]` for label-based indexing.

> Non-obvious behaviors

gotchas

- `m[j = 2

i = 1]` is `m[2

- `stl` result components: `$time.series` matrix with columns `seasonal`

`trend`

- `stl` requires `s.window` (seasonal window) — must be specified

no default. `s.window = periodic` assumes fixed seasonality.

- `decompose`: simpler than `stl`

uses moving averages. `type = additive` or `multiplicative`.

- `arima(x

order = c(p

- `format(object.size(x)

units = MB)` for human-readable output.

Data

- `ts(data

start

- `vignette()` lists all vignettes; `vignette(name

package = pkg)` opens a specific one.

- Update with `setTxtProgressBar(pb

value)`. Close with `close(pb)`.

- Style 1: rotating `|/-\`

style 2: simple progress. Only style 3 shows percentage.

- `txtProgressBar(min

max

Data

- `relist(flesh

skeleton)` — `flesh` is the flat data

- Works with factors

matrices

- Inverse of `unlist`: given a flat vector and a skeleton list

reconstructs the nested structure.

- `FUN` argument applies a function to each combination: `combn(5

- Does add new names not in `x` — it uses `x[names(val)] <- val` internally

so any name in `val` gets added or replaced.

- `modifyList(x

val)` replaces elements of list `x` with those in `val` by **name**.

- Checks attributes

names

- `combn(n

m)` or `combn(x

- Returns `TRUE` or a character string describing the difference — NOT `FALSE`. Use `isTRUE(all.equal(x

y))` in conditionals.

- Tests near equality with tolerance (default `1.5e-8`

i.e.

- Custom conditions: `stop(errorCondition(msg

class = myError))` then catch with `tryCatch(...