sliceByKey

sliceByKey(table, rowKeys, [colNames], [preserveOrder=false])

table is a keyed table or indexed table.

rowKeys is a scalar/vector indicating the specified values of key columns.

colNames (optional) is a string scalar/vector indicating the names of columns to be selected.

preserveOrder (optional) is a Boolean scalar indicating whether the result should maintain the input order of rowKeys. The default is false, meaning the output may not follow the specified order.

Get the rows containing the specified values of the key columns from a keyed table or an indexed table. It is faster than the corresponding SQL statement.

For a keyed table, rowKeys must contain values for all key columns.

For an indexed table, rowKeys must contain values for the first n key columns.

If colNames is not specified, return all columns.

The data form of the result depends on colNames. If colNames is a scalar, return a vector; if colNames is a vector, return an in-memory table.

t = indexedTable(`sym`side, 10000:0, `sym`side`price`qty, [SYMBOL,CHAR,DOUBLE,INT])
insert into t values(`IBM`MSFT`IBM, ['B','S','S'], 125.27 208.9 125.29, 1000 800 200)
a=sliceByKey(t,"IBM", 'price');

a;
// output: [125.27,125.29]

typestr(a);
// output: FAST DOUBLE VECTOR

a=sliceByKey(t,("IBM",'S'));
a;

typestr(a);
// output: IN-MEMORY TABLE

t1 = keyedTable(`sym`side, 10000:0, `sym`side`price`qty, [SYMBOL,CHAR,DOUBLE,INT])
insert into t1 values(`IBM`MSFT`IBM, ['B','S','S'], 125.27 208.9 125.29, 1000 800 200)
sliceByKey(t1, [["IBM", "MSFT"], ['B', 'S']]);

Specify preserveOrder=true to return results in the input order of the key columns.

sliceByKey(table=t1, rowKeys=[["MSFT", "IBM"], ['S', 'B']], preserveOrder=true);