Some ML Engine functions have column specification arguments with this syntax:
argument ( {'column' | column_range }[,...] )
The column is a column name. This is the syntax of column_range:
'start_column:end_column' [, '-exclude_column' ]
The range includes its endpoints.
The start_column and end_column can be:
- Column names (for example, 'column1:column2')
- Nonnegative integers that represent the indexes of columns in the table (for example, '[0:4]')
The first column has index 0; therefore, '[0:4]' specifies the first five columns in the table.
- Empty. For example:
- '[:4]' specifies all columns up to and including the column with index 4.
- '[4:]' specifies the column with index 4 and all columns after it.
- '[:]' specifies all columns in the table.
The exclude_column is a column in the specified range, represented by either its name or its index (for example, '[0:99]', '-[50]', '-column10' specifies the columns with indexes 0 through 99, except the column with index 50 and column10).
Column ranges cannot overlap, and cannot include any specified column.