ExtendedKey

ExtendedKey[key1,key2,…]

represents a multilevel column key in a Tabular object.

Details

  • ExtendedKey is used in functions such as Part to access values in Association objects or columns in Tabular objects.
  • ExtendedKey is typeset stacking the keyi as different levels of the column header. Shared upper keys will be typeset spanning the columns.

Examples

open allclose all

Basic Examples  (1)

Create a Tabular object with columns using ExtendedKey:

Extract the column keys:

Extract the columns corresponding to "obs A":

Scope  (2)

Take a Tabular object with ExtendedKey column keys:

Extract one column as a TabularColumn object:

Extract the same column as another Tabular object:

ExtendedKey[…,key] can be shortened to key if this uniquely identifies the column:

Take a Tabular object with ExtendedKey column keys:

Extract all columns sharing the specified keys:

Using patterns in ExtendedKey is interpreted as producing a list of keys, even if only one:

None of the column keys matches this structure:

Properties & Relations  (4)

ExtendedKey is stripped in associations when containing only one key:

The symbol remains when containing several keys:

Key lookup in associations requires exact matching:

Using ExtendedKey succeeds in all four cases:

ExtendedKey has Flat attribute:

Nested ExtendedKey wrappers will therefore be automatically flattened:

Key always takes one argument:

ExtendedKey can take more than one argument:

Both keys can then be used to address their values:

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

Text

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

CMS

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

APA

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

BibTeX

@misc{reference.wolfram_2024_extendedkey, author="Wolfram Research", title="{ExtendedKey}", year="2025", howpublished="\url{https://reference.wolfram.com/language/ref/ExtendedKey.html}", note=[Accessed: 15-January-2025 ]}

BibLaTeX

@online{reference.wolfram_2024_extendedkey, organization={Wolfram Research}, title={ExtendedKey}, year={2025}, url={https://reference.wolfram.com/language/ref/ExtendedKey.html}, note=[Accessed: 15-January-2025 ]}