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TreeRules[tree]

returns the rules associated with the Tree object tree.

Details
Details and Options Details and Options
Examples  
Basic Examples  
Scope  
Properties & Relations  
Possible Issues  
See Also
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TreeRules

TreeRules[tree]

returns the rules associated with the Tree object tree.

Details

  • TreeRules returns the rules associated with a tree expression.
  • The inverse operation of TreeRules is performed by RulesTree.
  • If tree has a list of children, then TreeRules[tree] gives data{rule1,rule2,…}, where data is the data in tree and rulei are the rules associated with its children.
  • TreeRules[Tree[data,<|key1tree1,key2tree2,…|>]] gives data<|key1TreeRules[tree1],key2TreeRules[tree2],…|>.
  • TreeRules[Tree[data,None]] for data of the form …{…}, …<|…|> or …None gives dataNone rather than data. »

Examples

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Basic Examples  (3)

Get the rules associated with a tree with three leaves:

Wolfram Language code: TreeRules[[image]]

Get the rules for a tree with several levels:

Wolfram Language code: TreeRules[[image]]

Get the rules for a tree with named edges:

Wolfram Language code: TreeRules[[image]]

Scope  (4)

Use TreeRules on a leaf with no child:

Wolfram Language code: TreeRules[[image]]

Use TreeRules on an inner node with no children:

Wolfram Language code: TreeRules[Tree[a, {}]]
Wolfram Language code: TreeRules[Tree[a, <||>]]

Use TreeRules on a tree with a list of children:

Wolfram Language code: TreeRules[[image]]

Use TreeRules on a tree with an association of children:

Wolfram Language code: TreeRules[[image]]

Properties & Relations  (2)

RulesTree constructs a tree associated with the given rules:

Wolfram Language code: RulesTree[a -> {b, c -> {}, d -> {e, f}}]

Use TreeRules on the result to recover the original rules:

Wolfram Language code: TreeRules[%]

TreeRules[tree] is generally equivalent to TreeFold[{Rule,Identity},tree]:

Wolfram Language code: TreeRules[[image]]
Wolfram Language code: % === TreeFold[{Rule, Identity}, [image]]

Possible Issues  (1)

TreeRules[Tree[data,None]] generally gives data:

Wolfram Language code: TreeRules[Tree[1, None]]

However, TreeRules[Tree[expr{…},None]] gives (expr{…})None instead:

Wolfram Language code: TreeRules[Tree[1 -> {2, 3}, None]]
Wolfram Research (2021), TreeRules, Wolfram Language function, https://reference.wolfram.com/language/ref/TreeRules.html (updated 2022).

Text

Wolfram Research (2021), TreeRules, Wolfram Language function, https://reference.wolfram.com/language/ref/TreeRules.html (updated 2022).

CMS

Wolfram Language. 2021. "TreeRules." Wolfram Language & System Documentation Center. Wolfram Research. Last Modified 2022. https://reference.wolfram.com/language/ref/TreeRules.html.

APA

Wolfram Language. (2021). TreeRules. Wolfram Language & System Documentation Center. Retrieved from https://reference.wolfram.com/language/ref/TreeRules.html

BibTeX

@misc{reference.wolfram_2026_treerules, author="Wolfram Research", title="{TreeRules}", year="2022", howpublished="\url{https://reference.wolfram.com/language/ref/TreeRules.html}", note=[Accessed: 13-June-2026]}

BibLaTeX

@online{reference.wolfram_2026_treerules, organization={Wolfram Research}, title={TreeRules}, year={2022}, url={https://reference.wolfram.com/language/ref/TreeRules.html}, note=[Accessed: 13-June-2026]}