Stata does not have the concept of a categorical variable, but statistical people do, as shown by many book titles alone (for example, Fienberg [1980]; Lloyd [1999]; Simonoff [2003]; Tutz [2012]; Agresti [2013]; Long and Freese [2014]). The categories of such variables are distinct and often, but not necessarily, few in number. Examples are differing disease condition, employment status, or land cover type. A categorical variable in Stata can be stored as string; as numeric with value labels; or sometimes as just numeric, as when the number of cars or cats or children in households is just a discrete count that you want to treat as categorical.

中文翻译：

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Stata Tip 140：带图形栏的类别标签更短或更少

Stata没有分类变量的概念，但统计人员却有，如仅许多书名所示（例如，Fienberg [1980]； Lloyd [1999]； Simonoff [2003]； Tutz [2012]； Agresti [2013] ]； Long and Freese [2014]）。这样的变量的类别是不同的，并且通常但不一定是数量很少。例如不同的疾病状况，就业状况或土地覆盖类型。Stata中的分类变量可以存储为字符串；带值标签的数字形式；或有时只是数字，例如家庭中的汽车，猫或儿童的数量只是您要视为分类的离散计数。