Questions tagged [traversal]

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5
votes
2answers
134 views

How to mark leaves of polynomial based on its position in tree

I've been struggling with this for a few days, and so I thought I might ask this here. Part of the problem lies in the fact that I do not even know the mathematical solution, which runs the risk of ...
7
votes
1answer
202 views

How to perform a depth-first in-order traversal of an expression?

To complement my earlier questions: How to perform a breadth-first traversal of an expression? How to perform a depth-first preorder traversal of an expression? I would now like to ask: how to ...
4
votes
3answers
215 views

a function to extract all subexpressions from an expression

Can somebody help me with a function f such that it extract all sub expressions (i.e. looking down the expression tree) from any expression given to it and also a ...
5
votes
1answer
161 views

How to make a postordered ReplaceAll that operates just once per subtree?

The answers to this question provide code for a function I'll call postOrderReplaceAll to replace from the inside-out: ...
3
votes
1answer
179 views

why Level does not sort output according to their levels

Consider this example: Level[a + f[x, y^n], {0, Infinity}] (*{a, x, y, n, y^n, f[x, y^n], a + f[x, y^n]}*) Why the output is sorted in this way. why not ...
3
votes
5answers
349 views

Take the next element in a nested list

My problem is the following: Consider a list of elements. To better understanding my following explanations, I would take this example: ...
4
votes
1answer
274 views

Forcing optimal solution for FindShortestTour

I use FindShortestTour as explained here and it works nicely for a small number of cities. However when I try this with as little as 16 cities, the given tour isn't ...
9
votes
1answer
282 views

Position with Except returns first item {0} and last item {}. Why?

Here is a simple list: l={1, 0, 2, 1, 0, 1, 0, 1, 2, 0, 2, 0, 1, 0, 1, 0, 0} To get the position of non-zero elements I use ...
16
votes
1answer
1k views

Visiting nodes in a tree bottom up

I have a problem that can be reduced to this one: Suppose I have an unbalanced (almost random) tree. The leaves of the tree have one property already set, and all vertex (including the leaves) have ...
31
votes
5answers
2k views

How to perform a depth-first preorder traversal of an expression?

Mathematica provides functions that perform a depth-first postorder traversal, or which use such a traversal, including: Scan, ...
26
votes
7answers
1k views

How to perform a breadth-first traversal of an expression?

Mathematica provides functions that perform a depth-first traversal, or which use such a traversal, including: Scan, Count, <...
14
votes
3answers
708 views

Determining all possible traversals of a tree

I have a list: B={423, {{53, {39, 65, 423}}, {66, {67, 81, 423}}, {424, {25, 40, 423}}}}; This list can be visualized as a tree using ...