TreeSelect

TreeSelect[tree, crit] picks out all subtrees treei of tree for which crit[treei] is True.

• TreeSelect[tree, crit, n] picks out the first n subtrees for which crit[treei] is True.
• TreeSelect[tree, crit, levelspec, n] picks out subtrees on levels specified by levelspec.
• TreeSelect[crit] represents an operator form of TreeSelect that can be applied to a tree.

Examples

tree = Tree[1, {Tree[2, {3, 4}], Tree[5, {6}]}];
TreeSelect[tree, EvenQ[TreeData[#]] &]

TreeSelect[tree, TreeLeafQ, 2]

Please visit the official Wolfram Language Reference for more details.