Documentation
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Overview ¶
Package data is refract's data layer: columnar, batch-oriented access to a table of values.
The interface returns whole typed columns, never one value at a time. Scalar access is the single easiest way to make a plotting library slow, and a columnar shape is also what lets a []float64-backed source be borrowed instead of copied.
Index ¶
- type Source
- type Table
- func (t *Table) Columns() []string
- func (t *Table) Float64(name string, v []float64) *Table
- func (t *Table) Float64Column(name string) ([]float64, bool)
- func (t *Table) Len() int
- func (t *Table) String(name string, v []string) *Table
- func (t *Table) StringColumn(name string) ([]string, bool)
- func (t *Table) Time(name string, v []time.Time) *Table
- func (t *Table) TimeColumn(name string) ([]time.Time, bool)
Constants ¶
This section is empty.
Variables ¶
This section is empty.
Functions ¶
This section is empty.
Types ¶
type Source ¶
type Source interface {
// Len reports the number of rows. Every column has this length.
Len() int
// Columns lists the available column names. The order is stable across
// calls on the same Source.
Columns() []string
// Float64Column returns a numeric column by name. ok is false if the
// column does not exist or is not numeric.
Float64Column(name string) (data []float64, ok bool)
// TimeColumn returns a time column by name. ok is false if the column does
// not exist or is not temporal.
TimeColumn(name string) (data []time.Time, ok bool)
// StringColumn returns a categorical column by name. ok is false if the
// column does not exist or is not textual.
StringColumn(name string) (data []string, ok bool)
}
Source exposes columnar, batch access to a table.
Implementations return read-only views: the caller must not mutate a returned slice, and refract never does. An implementation that already holds its data as a Go slice should return that slice directly rather than copying.
func Float64Columns ¶
Float64Columns builds a Source over the given numeric columns.
The slices are borrowed, not copied: the returned Source aliases the caller's memory, and mutating it afterwards mutates what refract will plot. All columns must have the same length; Float64Columns panics otherwise, because a ragged table is a programming error rather than a runtime condition.
type Table ¶
type Table struct {
// contains filtered or unexported fields
}
Table is a Source that mixes numeric, temporal and categorical columns.
It is the general-purpose implementation: use it when a chart plots time or a category against values, which is the common case for the Time and Ordinal scales.
func (*Table) Float64 ¶
Float64 adds a numeric column, borrowing the slice. It returns t so calls can be chained. It panics if the column length disagrees with columns already added, or if the name is already taken.
func (*Table) Float64Column ¶
Float64Column returns a numeric column by name.
func (*Table) String ¶ added in v0.2.0
String adds a categorical column, borrowing the slice. It returns t so calls can be chained. It panics if the column length disagrees with columns already added, or if the name is already taken.
Plot such a column against a [scale.Ordinal] axis; a continuous scale has no position for a category name and a geom says so rather than guessing one.
func (*Table) StringColumn ¶ added in v0.2.0
StringColumn returns a categorical column by name.
Source Files