WOLFRAM

Wolfram 语言与系统参考资料中心

RowKey[{key1,key2,…}]

表示一个键，可用于提取 Tabular 对象中关键列的值为 keyi 的行.

更多信息
Details and Options Details and Options
范例  
基本范例  
范围  
应用  
属性和关系  
参见
相关指南
历史
按以下格式引用：

RowKey

RowKey[{key1,key2,…}]

表示一个键，可用于提取 Tabular 对象中关键列的值为 keyi 的行.

更多信息

  • RowKey 通常用于获取 Tabular 对象的行.
  • 对于给定的 Tabular 对象， RowKey[{key1,key2,…}] 中的 keyi 列表必须唯一指定每一行.
  • RowKey[key] 被理解为 RowKey[{key}].
  • 对于 Tabular 对象 tab，RowKey[…][tab] 等价于 tab[RowKey[…]].

范例

打开所有单元 关闭所有单元

基本范例  (2)

创建有三个列的 Tabular 对象：

Wolfram Language code: Tabular[{{1, "a", 2.}, {4, "b", 3.}}, {"col1", "col2", "col3"}]

将其中之一设置为关键列，以允许按该列建立索引：

Wolfram Language code: tab = Tabular[%, <|"KeyColumns" -> {"col2"}|>]

提取关键列含有 "b" 的行：

Wolfram Language code: tab[RowKey[{"b"}]]
Wolfram Language code: %//Normal

使用 RowKey[…] 作为函数，从带有键列的 Tabular 对象中提取一行：

Wolfram Language code: EntityValue[{Entity["Country", "France"], Entity["Country", "Italy"]}, {"GDP", "Area"}, "Tabular"]
Wolfram Language code: %//RowKey[Entity["Country", "France"]]// Normal

范围  (3)

创建含有关键列的 Tabular 对象：

Wolfram Language code: tab = Tabular[{{"a", 2.}, {"b", 3.}}, <|"ColumnKeys" -> {"col1", "col2"}, "KeyColumns" -> {"col1"}|>]

提取关键列中含有 "a" 的行：

Wolfram Language code: tab[RowKey[{"a"}]]
Wolfram Language code: %//Normal

当只有一个关键列时，不需要 List 封装：

Wolfram Language code: tab[RowKey["a"]]

将 RowKey[…] 用作函数，应用到 Tabular 对象：

Wolfram Language code: RowKey[{"b"}][Tabular[Association["RawSchema" -> Association["ColumnProperties" -> Association["col1" -> Association["ElementType" -> "String"], "col2" -> Association["ElementType" -> "Real64"]], "KeyColumns" -> {"col1"}, "Backend" -> "WolframKernel"], "Options" -> {}, "BackendData" -> Association["ColumnData" -> DataStructure["ColumnTable", {{TabularColumn[Association["Data" -> {{3, {0, 1, 2}, "ab"}, {}, None}, "ElementType" -> "String"]], TabularColumn[Association["Data" -> {{2., 3.}, {}, None}, "ElementType" -> "Real64"]]}}]]]]]

获取一个含有 G7 国家人口的 Tabular 对象：

Wolfram Language code: tab = Tabular[Association["RawSchema" -> Association["ColumnProperties" -> Association["Year" -> Association["ElementType" -> "Integer64"], "Country" -> Association["ElementType" -> "String"], "Population" -> Association["ElementType" -> TypeSpecifier["Quantity"]["Real64", "People"]]], "KeyColumns" -> None, "Backend" -> "WolframKernel"], "BackendData" -> Association["ColumnData" -> DataStructure["ColumnTable", {{TabularColumn[Association["Data" -> {{1950, 1950, 1950, 1950, 1950, 1950, 1950, 2000, 2000, 2000, 2000, 2000, 2000, 2000}, {}, None}, "ElementType" -> "Integer64"]], TabularColumn[Association["Data" -> {{3, {0, 6, 12, 19, 24, 29, 42, 54, 60, 66, 73, 78, 83, 96, 108}, "CanadaFranceGermanyItalyJapanUnitedKingdomUnitedStatesCanadaFranceGermanyI\ talyJapanUnitedKingdomUnitedStates"}, {}, None}, "ElementType" -> "String"]], TabularColumn[Association["Data" -> {14, {{{1.3737*^7, 4.1828673*^7, 6.8377*^7, 4.7104*^7, 8.31996*^7, 5.0127*^7, 1.513258*^8, 3.0529607*^7, 5.8494936*^7, 8.1561598*^7, 5.6950733*^7, 1.26664952*^8, 5.8734782*^7, 2.80816627*^8}, {}, None}}, None}, "ElementType" -> TypeSpecifier["Quantity"]["Real64", "People"]]]}}]]]];

将两列设置为关键列：

Wolfram Language code: Tabular[tab, <|"KeyColumns" -> {"Year", "Country"}|>]

用 RowKey 提取给定列的值：

Wolfram Language code: %[RowKey[{2000, "Italy"}], "Population"]

应用  (1)

获取每个州致命撞车事故的表格数据：

Wolfram Language code: tab = ResourceData["Sample Tabular Data: Fatal Collisions"]
Wolfram Language code: ColumnKeys[tab]

没有指定关键列：

Wolfram Language code: Keys[tab]

对列重新排序，将 "state" 列设为关键列：

Wolfram Language code: neworder = RotateRight[ColumnKeys[tab]]
Wolfram Language code: newtab = Tabular[tab[All, neworder], <|"KeyColumns" -> {"state"}|>]
Wolfram Language code: Keys[newtab]

提取美国中西部各州的行：

Wolfram Language code: midwest = EntityValue[EntityClass["AdministrativeDivision", "USStatesMidwest"], EntityProperty["AdministrativeDivision", "StateAbbreviation"]]
Wolfram Language code: Tabular[newtab[RowKey[#]]& /@ midwest, <|"KeyColumns" -> {"state"}|>]

属性和关系  (4)

下面是含有关键列的 Tabular 对象：

Wolfram Language code: tab = Tabular[{{"one", True, "foo"}, {"two", False, "bar"}}, <|"ColumnKeys" -> {"key", "col1", "col2"}, "KeyColumns" -> {"key"}|>]

可用 RowKey 提取行：

Wolfram Language code: tab[RowKey["one"]]

也可用 Key 封装提取表格中的行：

Wolfram Language code: tab[Key["one"]]

如果指定了关键列，Tabular 对象的 Keys 返回 RowKey 表达式列表：

Wolfram Language code: Tabular[{{"cat", 2, 3}, {"dog", 5, 6}}, <|"ColumnKeys" -> {"a", "b", "c"}, "KeyColumns" -> {"a"}|>]
Wolfram Language code: Keys[%]

有多个关键列的情况：

Wolfram Language code: Tabular[{{"cat", 2, 3}, {"dog", 5, 6}}, <|"ColumnKeys" -> {"a", "b", "c"}, "KeyColumns" -> {"a", "b"}|>]
Wolfram Language code: Keys[%]

RowKey[{key1,key2,…}] 允许通过多个关键列的值对行进行索引：

Wolfram Language code: Tabular[Association["RawSchema" -> Association["ColumnProperties" -> Association["a" -> Association["ElementType" -> "String"], "b" -> Association["ElementType" -> "Integer64"], "c" -> Association["ElementType" -> "Integer64"]], "KeyColumns" -> {"a", "b"}, "Backend" -> "WolframKernel"], "BackendData" -> Association["ColumnData" -> DataStructure["ColumnTable", {{TabularColumn[Association["Data" -> {{3, {0, 3, 6}, "catdog"}, {}, None}, "ElementType" -> "String"]], TabularColumn[Association["Data" -> {{2, 5}, {}, None}, "ElementType" -> "Integer64"]], TabularColumn[Association["Data" -> {{3, 6}, {}, None}, "ElementType" -> "Integer64"]]}}]]]][RowKey[{"cat", 2}]]
Wolfram Language code: %//Normal

ExtendedKey[key1,key2,…] 允许通过多个值指定列：

Wolfram Language code: Tabular[Association["RawSchema" -> Association["ColumnProperties" -> Association[ExtendedKey["female", "name"] -> Association["ElementType" -> "String"], ExtendedKey["female", "city"] -> Association["ElementType" -> "String"]], "KeyColumns" -> None, "Backend" -> "WolframKernel"], "BackendData" -> Association["ColumnData" -> DataStructure["ColumnTable", {{TabularColumn[Association["Data" -> {{3, {0, 4, 13}, "AnnaElizabeth"}, {}, None}, "ElementType" -> "String"]], TabularColumn[Association[ "Data" -> {{3, {0, 7, 12}, "ChicagoParis"}, {}, None}, "ElementType" -> "String"]]}}]]]][All, ExtendedKey["female", "city"]]
Wolfram Language code: %//Normal

RowKey 可以包含与 ExtendedKey 对象指定的列相对应的键：

Wolfram Language code: tab = Tabular[Association["RawSchema" -> Association["ColumnProperties" -> Association[ExtendedKey["first", "name"] -> Association["ElementType" -> "String"], ExtendedKey["first", "a"] -> Association["ElementType" -> "Integer64"], ExtendedKey["first", "b"] -> Association["ElementType" -> "Integer64"], ExtendedKey["second", "name"] -> Association["ElementType" -> "String"], ExtendedKey["second", "a"] -> Association["ElementType" -> "Integer64"], ExtendedKey["second", "b"] -> Association["ElementType" -> "Integer64"]], "KeyColumns" -> {ExtendedKey["first", "name"], ExtendedKey["second", "name"]}, "Backend" -> "WolframKernel"], "Options" -> {}, "BackendData" -> Association["ColumnData" -> DataStructure["ColumnTable", {{TabularColumn[Association["Data" -> {{3, {0, 3, 6}, "catdog"}, {}, None}, "ElementType" -> "String"]], TabularColumn[Association["Data" -> {{2, 5}, {}, None}, "ElementType" -> "Integer64"]], TabularColumn[Association["Data" -> {{3, 6}, {}, None}, "ElementType" -> "Integer64"]], TabularColumn[Association[ "Data" -> {{3, {0, 4, 9}, "rosetulip"}, {}, None}, "ElementType" -> "String"]], TabularColumn[Association["Data" -> {{7, 10}, {}, None}, "ElementType" -> "Integer64"]], TabularColumn[Association["Data" -> {{8, 11}, {}, None}, "ElementType" -> "Integer64"]]}}]]]];
Wolfram Language code: tab[RowKey[{"cat", "rose"}]]
Wolfram Language code: %//Normal
Wolfram Research (2025)，RowKey，Wolfram 语言函数，https://reference.wolfram.com/language/ref/RowKey.html.

文本

Wolfram Research (2025)，RowKey，Wolfram 语言函数，https://reference.wolfram.com/language/ref/RowKey.html.

CMS

Wolfram 语言. 2025. "RowKey." Wolfram 语言与系统参考资料中心. Wolfram Research. https://reference.wolfram.com/language/ref/RowKey.html.

APA

Wolfram 语言. (2025). RowKey. Wolfram 语言与系统参考资料中心. 追溯自 https://reference.wolfram.com/language/ref/RowKey.html 年

BibTeX

@misc{reference.wolfram_2026_rowkey, author="Wolfram Research", title="{RowKey}", year="2025", howpublished="\url{https://reference.wolfram.com/language/ref/RowKey.html}", note=[Accessed: 13-July-2026]}

BibLaTeX

@online{reference.wolfram_2026_rowkey, organization={Wolfram Research}, title={RowKey}, year={2025}, url={https://reference.wolfram.com/language/ref/RowKey.html}, note=[Accessed: 13-July-2026]}