FromStructs()#

Description#

FromStructs() creates a Table from a slice of structs.

This constructor allows you to convert in-memory structured data into a Table by using reflection. Each exported field of the struct becomes a column, and each element in the slice becomes a row.

Signature#

FromStructs[T any](rows []T) (*Table, error)

Parameters#

rows
A slice of structs used as the data source for the Table.

Struct Field Rules#

Only exported fields are included.
Fields can be customized using struct tags.
A custom column name can be provided via the `rowan` tag.
Fields tagged with `rowan:"-"` are ignored.

Return Values#

*Table
A pointer to the resulting Table constructed from the struct slice.
error
An error is returned if the input slice is empty or does not contain structs.

Behavior#

Inspects the struct type using reflection.
Uses exported struct fields as columns.
Iterates over each struct in the slice to populate table rows.
Returns an error if:
- The slice is empty.
- The element type is not a struct.

Notes#

Field order in the struct determines column order in the Table.
All values are stored as []any and may require type conversion for numeric operations.
Struct tags provide full control over column naming and inclusion.

Example Usage#

See this example for practical usage of FromStructs() and seeing how struct tags affect the resulting columns.

Assume we have Member struct as below:

type Member struct {
  Name   string
  Age    int     `rowan:"-"`
  Score  float32 `rowan:"Average Point"`
  Active bool    `rowan:"Status"`
}

The following code demonstrates creating a Table from a slice of Member instances.

memberSlice := []Member{
  {Name: "Alice", Age: 21, Score: 88.5, Active: true},
  {Name: "Bob", Age: 20, Score: 92, Active: false},
  {Name: "Charlie", Age: 18, Score: 79.25, Active: true},
}

tbl, _ := rowan.FromStructs(memberSlice)

tbl.First().Display()
tbl.Overview()

Output:

------------------------------------
|  Name   | Average Point | Status |
------------------------------------
| Alice   |     88.50     |  true  |
| Bob     |     92.00     | false  |
| Charlie |     79.25     |  true  |
------------------------------------

Table Overview
Rows: 3
Columns:
--------------------------
|     Name      |  Type  |
--------------------------
| Name          | string |
| Average Point | float  |
| Status        | bool   |
--------------------------