Description:
Define a computation on a pseudo table, which will group its records and write the grouped subsets to a sequence of bin files.
Syntax:
T.groupn(x;F)
Note:
The function defines a computation on pseudo table T, which will group its records by grouping expression x and write the grouped subsets to a sequence of bin files F, and return a new pseudo table.
Parameter:
|
T |
A pseudo table |
|
x |
Grouping expression |
|
F |
Return value:
Pseudo table
Example:
|
|
A |
|
|
1 |
=create(file).record(["empAll.ctx"]) |
|
|
2 |
=pseudo(A1) |
Generate a pseudo table from the composite table. |
|
3 |
=[file("f_dept.btx"),file("m_dept.btx")] |
Return a sequence of bin file objects |
|
4 |
=A2.groupn(if(GENDER=="F",1,2);A3) |
Define a computation on A2’s pseudo table, which will put records where GENDER is F into the first group and the other records into the second group and write the grouped subsets into a sequence of bin files correspondingly. |
|
5 |
=A4.cursor().fetch() |
Fetch data from A4’s pseudo table, when the grouped subsets are actually written to bin files. |