update_

swordfish.function.update_()

Update columns of a table in place. If a column in colNames doesn't exist, create a new column; otherwise update the existing column. If a filter is specified, only rows satisfying the filtering condition will be updated.

This operation is parallel if the table is a partitioned table and if the parallel processing feature is enabled (when the configuration parameter localExcutors > 0).

参数:

• table (Constant) -- A DolphinDB table. It can be a partitioned in-memory table.

• colNames (Constant) -- A string scalar/vector indicating the columns to be updated.

• newValues (Constant) -- A piece of metacode with the operations for the specified columns. Metacode is objects or expressions within "<" and ">". For details about metacode, please refer to Metaprogramming.

• filter (Constant, optional) -- A a piece of metacode with filterting conditions, by default DFLT.