# `cube_extract()`
**Category:** Selection and extraction
**Status:** stable

## Purpose
Extract values as tidy tables, series, or profiles.

## When to use
Use it when its declared input and output match the workflow. Prefer a narrower selection before any operation that may materialise values.

## When not to use
Do not use it to calculate `spatind` indicators or to bypass coordinate, CRS, unit, and provenance checks.

## Real signature
```r
cube_extract(x, longitude = NULL, latitude = NULL, depth = NULL,      time = NULL, variable = NULL, by = c("value", "index"), match = c("exact",          "nearest"), tolerance = NULL, mode = c("point", "profile",          "series", "table"), format = c("long", "wide"), keep_index = FALSE,      keep_distance = FALSE)
```

## Arguments
- `x`: see the installed Rd manual for validation and defaults.
- `longitude`: see the installed Rd manual for validation and defaults.
- `latitude`: see the installed Rd manual for validation and defaults.
- `depth`: see the installed Rd manual for validation and defaults.
- `time`: see the installed Rd manual for validation and defaults.
- `variable`: see the installed Rd manual for validation and defaults.
- `by`: see the installed Rd manual for validation and defaults.
- `match`: see the installed Rd manual for validation and defaults.
- `tolerance`: see the installed Rd manual for validation and defaults.
- `mode`: see the installed Rd manual for validation and defaults.
- `format`: see the installed Rd manual for validation and defaults.
- `keep_index`: see the installed Rd manual for validation and defaults.
- `keep_distance`: see the installed Rd manual for validation and defaults.

## Input and output
Input: **ocean_cube**. Output: **data.frame**.

## Backend support
Memory: **TRUE**. NetCDF: **TRUE**. Backend operations retain read-only semantics; materialisation is explicit.

## Dimensional effect
May change shape or return a non-cube analytical object; inspect dimensions/rows.

## Metadata
Units, coordinates, provenance, masks, and QA metadata are retained or reported where meaningful.

## Minimal executable check
```r
library(oceancube)
stopifnot(is.function(oceancube::cube_extract))
names(formals(oceancube::cube_extract))
```

## Example in a workflow
Typical position: `cube_slice/cube_crop` → `cube_extract()` → `spatind/data analysis`. See the workflow scripts for a checked end-to-end example.

## Frequent errors and limitations
Invalid dimensions, selectors, units, CRS, source-file identity, optional dependencies, or unsupported grids are rejected explicitly. Read the function Rd page for exact diagnostics.

## Related functions
Previous: `cube_slice/cube_crop`. Next: `spatind/data analysis`.