ColumnKeys

ColumnKeys[tab]

gives a list of the column keys in the Tabular object tab.

ColumnKeys[tab,spatt]

gives the column keys of tab that match the string pattern spatt.

ColumnKeys[tab,crit]

gives the column keys keyi of tab for which crit[keyi] is True.

Details

  • ColumnKeys is typically used to get a list of column keys or search for specific keys.
  • ColumnKeys returns column keys in the same order in which they appear in the Tabular object.
  • For a Tabular object tab with anonymous columns, ColumnKeys[tab,…] returns None.
  • In ColumnKeys[tab,spatt], possible string patterns include strings with wild characters, such as "col*" and StringExpression objects such as "col"~~__.
  • In ColumnKeys[tab,crit], the function crit takes named variables #ColumnKey, providing the column key, and #ElementType, providing the type of the elements of the column.

Examples

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Basic Examples  (3)

Get the list of column keys:

Select the keys that have names matching a string pattern:

Select the keys obeying a criterion function:

Scope  (8)

Get the column keys of a Tabular object:

Get the column keys of a Dataset object:

Get the keys of a list of associations:

ColumnKeys gives the unsorted union of the keys of the associations:

The result is also consistent with the corresponding Tabular object:

The column keys of a Tabular object can be arbitrary expressions:

Take a Tabular object:

Use string patterns to select the columns whose key ends in "1":

Use a criterion function to select the keys of columns with integers:

Get the column keys for multilevel column names:

Key columns are included in the result of ColumnKeys:

For a Tabular object with unspecified column keys, ColumnKeys returns None:

Properties & Relations  (1)

ColumnKeyExistsQ[tab,key] returns True if key is in the list ColumnKeys[tab]:

Wolfram Research (2025), ColumnKeys, Wolfram Language function, https://reference.wolfram.com/language/ref/ColumnKeys.html.

Text

Wolfram Research (2025), ColumnKeys, Wolfram Language function, https://reference.wolfram.com/language/ref/ColumnKeys.html.

CMS

Wolfram Language. 2025. "ColumnKeys." Wolfram Language & System Documentation Center. Wolfram Research. https://reference.wolfram.com/language/ref/ColumnKeys.html.

APA

Wolfram Language. (2025). ColumnKeys. Wolfram Language & System Documentation Center. Retrieved from https://reference.wolfram.com/language/ref/ColumnKeys.html

BibTeX

@misc{reference.wolfram_2024_columnkeys, author="Wolfram Research", title="{ColumnKeys}", year="2025", howpublished="\url{https://reference.wolfram.com/language/ref/ColumnKeys.html}", note=[Accessed: 15-January-2025 ]}

BibLaTeX

@online{reference.wolfram_2024_columnkeys, organization={Wolfram Research}, title={ColumnKeys}, year={2025}, url={https://reference.wolfram.com/language/ref/ColumnKeys.html}, note=[Accessed: 15-January-2025 ]}