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TreeLeafCount[tree]

gives the number of leaves of tree.

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TreeLeafCount

TreeLeafCount[tree]

gives the number of leaves of tree.

Details

Examples

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Basic Examples  (1)

Count the leaves in a tree:

Wolfram Language code: TreeLeafCount[[image]]

Applications  (1)

Randomly generated trees with n nodes have n/2 leaves on average:

Wolfram Language code: Histogram[TreeLeafCount /@ RandomTree[40, 1000]]

Properties & Relations  (8)

TreeLeafCount[tree] is equivalent to Length[TreeSelect[tree,TreeLeafQ]]:

Wolfram Language code: TreeLeafCount[[image]]
Wolfram Language code: % === Length[TreeSelect[[image], TreeLeafQ]]

TreeLeafCount[tree] is equivalent to Length[TreeLeaves[tree]]:

Wolfram Language code: TreeLeafCount[[image]]
Wolfram Language code: % === Length[TreeLeaves[[image]]]

TreeLeafCount[tree] is equivalent to TreeCount[tree,_,{-1}]:

Wolfram Language code: TreeLeafCount[[image]]
Wolfram Language code: % === TreeCount[[image], _, {-1}]

TreeLeafCount[Tree[{tree1,tree2,…}]] gives TreeLeafCount[tree1]+TreeLeafCount[tree2]+…:

Wolfram Language code: TreeLeafCount[[image]]
Wolfram Language code: % === TreeLeafCount[[image]] + TreeLeafCount[[image]]

TreeLeafCount[Tree[data,None]] gives 1:

Wolfram Language code: TreeLeafCount[[image]]

TreeLeafCount[Tree[data,{}]] gives 0:

Wolfram Language code: TreeLeafCount[[image]]

TreeSize[Tree[data,{}]] gives 1:

Wolfram Language code: TreeSize[[image]]

TreeLeafCount can be computed using TreeFold:

Wolfram Language code: TreeLeafCount[[image]]
Wolfram Language code: % === TreeFold[{Total@#2&, 1&}, [image]]

LeafCount[expr] is generally equivalent to TreeLeafCount[ExpressionTree[expr,"Subexpressions",HeadsTrue]]:

Wolfram Language code: LeafCount[1[2[4[8, 9], 5[10]], 3[6, 7]]]
Wolfram Language code: ExpressionTree[1[2[4[8, 9], 5[10]], 3[6, 7]], "Subexpressions", Heads -> True]
Wolfram Language code: TreeLeafCount[%]

LeafCount[expr,HeadsFalse] is generally equivalent to TreeLeafCount[ExpressionTree[expr,"Subexpressions"]]:

Wolfram Language code: LeafCount[1[2[4[8, 9], 5[10]], 3[6, 7]], Heads -> False]
Wolfram Language code: ExpressionTree[1[2[4[8, 9], 5[10]], 3[6, 7]], "Subexpressions"]
Wolfram Language code: TreeLeafCount[%]
Wolfram Research (2022), TreeLeafCount, Wolfram Language function, https://reference.wolfram.com/language/ref/TreeLeafCount.html.

Text

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

CMS

Wolfram Language. 2022. "TreeLeafCount." Wolfram Language & System Documentation Center. Wolfram Research. https://reference.wolfram.com/language/ref/TreeLeafCount.html.

APA

Wolfram Language. (2022). TreeLeafCount. Wolfram Language & System Documentation Center. Retrieved from https://reference.wolfram.com/language/ref/TreeLeafCount.html

BibTeX

@misc{reference.wolfram_2026_treeleafcount, author="Wolfram Research", title="{TreeLeafCount}", year="2022", howpublished="\url{https://reference.wolfram.com/language/ref/TreeLeafCount.html}", note=[Accessed: 15-June-2026]}

BibLaTeX

@online{reference.wolfram_2026_treeleafcount, organization={Wolfram Research}, title={TreeLeafCount}, year={2022}, url={https://reference.wolfram.com/language/ref/TreeLeafCount.html}, note=[Accessed: 15-June-2026]}