Questions tagged [traversal]
The traversal tag has no usage guidance.
12
questions
33
votes
5
answers
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, ...
- 270k
28
votes
7
answers
2k
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, <...
- 270k
16
votes
2
answers
2k
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 ...
- 115k
14
votes
3
answers
752
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 ...
- 10.4k
12
votes
1
answer
428
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 ...
- 547
9
votes
1
answer
431
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 ...
- 270k
5
votes
3
answers
356
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 ...
- 9,113
5
votes
1
answer
218
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:
...
- 434
5
votes
2
answers
155
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 ...
- 19.5k
4
votes
1
answer
308
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 ...
- 141
3
votes
1
answer
214
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 ...
- 19.7k
3
votes
5
answers
470
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:
...
- 616