crdate num format=DATETIME informat=DATETIME label='Date Created', 可以根据数据集的创建时间来控制 modate num format=DATETIME informat=DATETIME label='Date Modified', 可以根据数据集的修改时间来控制 nobs num label='Number of Physical Observations', obslen num label='Observation Length', nvar num label='Number of Variables', delobs num label='Number of Deleted Observations', nlobs num label='Number of Logical Observations', maxvar num label='Longest variable name', maxlabel num label='Longest label', num_character num label='Number of Character Variables', num_numeric num label='Number of Numeric Variables' |