创建有三个列的 Tabular 对象：

将其中之一设置为关键列，以允许按该列建立索引：

提取关键列含有 "b" 的行：

也可以将 RowKey[…] 用作函数：

Create a Tabular object with a key column:

Extract the row containing "a" in the key column:

The List wrapper is not needed when there is a single key column:

Use RowKey[…] as a function acting on a Tabular object:

取一个含有 G7 国家人口的 Tabular 对象：

将两列设置为关键列：

用 RowKey 提取给定列的值：

Take tabular data of fatal collisions for each state:

There are no key columns specified:

Reorder the columns and set the "state" column as key column:

Extract the rows for US Midwest states:

Take a Tabular object with a key column:

Row extraction can be performed with RowKey:

Key wrappers can also be used to extract a tabular row:

Keys of a Tabular object returns a list of RowKey expressions if key columns are specified:

For multiple key columns:

RowKey[{key₁,key₂,…}] allows indexing rows by the values of multiple key columns:

ExtendedKey[key₁,key₂,…] allows specifying columns by multiple values:

RowKey can contain keys corresponding to columns specified by ExtendedKey objects: