9.3.7: `delete'

`delete .variable.|\synonym [.variable.|\synonym [...]]'
`delete columns [where missing]'
`delete columns [randomly .fraction.]'
`delete grid'
`delete [x|y] scale'

Delete some item or characteristic.

• `delete .variable.' Delete definition of variable `.variable.', making it undefined. Any number of variables or synonyms may be specified on one line.

• `delete \synonym' Delete definition of synonym `\synonym', making it undefined. Any number of variables or synonyms may be specified on one line.

• `delete \@alias' Delete the item named by the alias (see Alias Synonyms).

• `delete' with an `&' item Delete the item in the calling program.

• `delete columns' Delete column data.

• `delete columns where missing' Completely delete all column data for which any one of x, y, etc is missing.

• `delete columns randomly .fraction.' Randomly select fraction `.fraction.' of the non-missing column data, and designate them as being missing.

• `delete grid' Delete grid data.

• `delete scale' Delete scales for both x and y, so next `read columns' will set it.

• `delete x scale' Delete scales for x, so next `read columns' will set it.

• `delete y scale' Delete scales for y, so next `read columns' will set it.