Questions on using or implementing more or less common data structures such as linked lists, structs, trees, tries, heaps etc. in Mathematica.

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0answers
38 views

Data structures in mathematica for choosing permutations

I am trying to classify permutations of n, in this case n=6, elements depending on the cycles that contian the points 1 and 2, since these are considered to be special points. So for example, I will ...
3
votes
1answer
70 views

Dealing with a large number of optimizations performed with parameters read in from a CSV file

I have a large CSV file (1.5M rows), with each row containing a set of parameters that I need for an optimization routine in Mathematica. I'm hoping to import the data, run the computation, and then ...
0
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1answer
55 views

Manipulation of imported Datafile

Since I am solving a differential equation in a for loop with NDSolve ...
2
votes
0answers
41 views

How to implement shared data structures?

If I have a shared data structure like you would find in nested C structs, how would I best implement that in Mathematica? I have some "object-oriented" code I would like to port to Mathematica. It's ...
7
votes
1answer
51 views

KaryTree of Text .csv and Correlation

How can I make a KaryTree of this raw-data (raw-data at the end of the question): This is is data from a political survey in which I ask 5 questions with the following possible answers: Q1: 'Y'= ...
2
votes
0answers
46 views

How to use a picture to store some data [duplicate]

As we know.The values of the types is "Real" defaultly in Mathematica.In the Image documentation's detail we can see Image[...
3
votes
1answer
108 views

Immutability, Association and typing

I have read the article by Leonid on the question. I am still struggling. I am trying to use Association to inject some pseudo-typing in my code. Here is my ...
0
votes
0answers
23 views

Mapping Functions to Associations [duplicate]

If I have the association matrix listed bellow and I want to apply: ...
1
vote
2answers
64 views

Creating Association [duplicate]

I have provided a dataset bellow and I would like to store the data as an Association that I can query. Such that e.g. ...
2
votes
2answers
85 views

Merge two trees into a rectangular matrix in Mathematica

How can I merge two trees, t and s, so as to form a square matrix below, where both trees starts from top-left (as shown), and ...
10
votes
7answers
272 views

Extract left-upper triangular data from a square matrix-form list

Hopefully, this question is not too basic or obscure. I'd like an idea on how to extract this {{1}, {5, 2}, {9, 6, 3}, {13, 10, 7, 4}} from ...
4
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0answers
53 views

How to transform a tree-form list to matrix-form list in Mathematica? [closed]

Excuse my naive question. Is there a quick/efficient way to transform {{1}, {1, 2}, {1, 2, 3}, {1, 2, 3, 4}} to a lower-triangular matrix-form ...
0
votes
1answer
170 views

How to fit multiple Gaussian peaks to data [duplicate]

How would I fit this data with Gaussian Peaks? I have tried various codes but none have even worked. Note: If I do Log[data], the peaks are more visible (I have tried the method from here but it got ...
1
vote
1answer
117 views

Fitting multiple peaks

I am using the code found here to fit multiple peaks of a large dataset which I don't know anything about. This was the only code I could find on the internet to do such a thing. So this is my attempt ...
0
votes
0answers
21 views

Remove background from multipeak data [duplicate]

Let's say I have a a very large list of data in the format {{n,f[n]}} so something like {{1,600},{2,700},{3,1100}...} and if this data is plotted, then it will look like a sum of Gaussian functions+a ...
1
vote
0answers
34 views

Repeat code segment from certain cell [closed]

If I have a lot of code and wish to repeat it in a different cell, but with some variables changed, how do I do it? (without copying and pasting) I tried using GoTo and Label but it did not recognize ...
1
vote
1answer
148 views

Resampling Data using Temporal Data

I am having a problem using TemporalData. I am simulating a two state system, and every time the system goes into a new state (which happens randomly), then I put ...
2
votes
0answers
57 views

Arrays with two different types of indices

Is there a way of having arrays which have, so to speak, two different depths $m,n$? From the point of view of memory usage, it would be the same as an array of depth $m+n$, but I would like to ...
1
vote
1answer
120 views

Turning table into association for Classify

I have the following sample data for 20 users. I know their sex, and the response for three yes/no questions. I am trying to building a classifier to guess their response to the third question, based ...
5
votes
3answers
353 views

Selecting numbers from a list

If I wish to select numbers which are greater than 2 or less than 1, I use the following codes respectively: ...
1
vote
2answers
139 views

Short way to query Dataset by the value of several columns

I learned how to query Dataset for rows that contain a certain value, but now I need to query for a long series of And in chain ...
25
votes
2answers
799 views

Dataset vs an association of associations

Associations with a record structure (e.g., a flat table) can be organised in one of two main ways. First as a list of associations, which is also used in the case of Mathematica's data set ...
1
vote
0answers
112 views

Custom Head for Encapsulation

Often when I'm writing a project in Mathematica, the number of arguments I must provide to functions spins out of control. I need a sort of object-oriented encapsulation approach. I've already had a ...
1
vote
0answers
244 views

Integration of graphs with datasets

Mathematica has a rich family of graph algorithms. I would like to leverage some of these for a very large tree structure. Because of the size of the structure, I would like to store it in a Dataset ...
2
votes
0answers
110 views

AVL binary search tree implementation

Is there any text-book implementation of self-balancing binary search trees such as AVL or red-black in Mathematica?
17
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1answer
280 views

Why do lookup times in Dataset and Association differ by orders of magnitude?

Consider the following three data structures: a list of rules, an association, and a dataset: ...
0
votes
1answer
140 views

Import and export without changing number format

I have a complex file that is the output of a program. The file contains multiple columns with data in different number formats. For example: ...
3
votes
0answers
121 views

Does Mathematica support an unordered set (e.g. hashset) data structure?

Does Mathematica support any data structure representing an unordered set (without multiplicity) of Mathematica expressions? I would like this data structure to support $O(1)$ insertion, deletion, and ...
2
votes
0answers
59 views

Does Mathematica support out-of-core Associations?

I often find myself collecting data in an Association[] which outgrows my computer's main memory. Does Mathematica support any out-of-core equivalent? Ideally, I ...
3
votes
2answers
199 views

Entropy of the elements of a general data set

I have the following data set, and wish to track the evolution of the entropy of each element within the set. I have evaluated the entropy for some elements, but how does one evaluate the entropy of ...
3
votes
4answers
119 views
2
votes
1answer
153 views

ordered tree data structure

I have a map $f:X\to \mathbb{N}$ and I wish to find $x,x'\in X$ such that $f(x)=f(x')$. Since such elements are rare, I will have to check very many elements and perform many comparisons, so I suspect ...
3
votes
1answer
114 views
4
votes
1answer
145 views

Parsing string with nested information

I am trying to parse a string, but I have no idea how to solve the following problem ...
6
votes
2answers
488 views

How would I programmatically add a row to a Dataset?

I would like to use a Dataset to track the process of a lengthy calculation over a large volume of material. Dataset appeals to me because of the power of the queries and it also looks like it may ...
5
votes
1answer
169 views

Filtering Query Nested Data (Dataset and Association)

I am trying to filter a nested Dataset. I have some data that looks like this (curated for this example): ...
2
votes
1answer
166 views

Structure of KernelMixtureDistribution and SmoothKernelDistribution

I would like to know more about the structure behind the KernelMixtureDistribution and SmoothKernelDistribution in Mathematica. ...
21
votes
1answer
283 views

Make my data-structure atomic

Lately, and by lately I mean since version 7 or so, the number of atomic expressions in Mathematica constantly grew. In former times only the native types like integers and optimised arrays were ...
0
votes
1answer
117 views

Right data format when EmpiricalDistribution expects “Rectangular Array”

I have the following code to generate random data (these are the eigenvalues of a non-central Wishart matrix, and I am interested in their distribution). ...
15
votes
1answer
280 views

Why won't SparseArray let me store values with the head List?

When you attempt to define a SparseArray with elements that have the head List it complains: ...
3
votes
3answers
211 views

Breaking up combined data into several smaller data sets

I have one combined data with first number as the x-value and the remaining as different y-axis values (y1,y2,y3...). How do I break this combined list, data= (x,y1,y2,y3...) into smaller lists, such ...
14
votes
0answers
446 views

Learning Resources for Data Science in the Wolfram Language

I'm delivering an upcoming course on Data Science with the programming/analysis done predominantly in the Wolfram Language. I created the following table to leverage students' familiarity with Lists ...
15
votes
3answers
925 views

Converting hierarchies of rules to associations

The impossibility of MatchQ-ing inside and Association MatchQ-ing Associations (MMA 10) explains a problem I have. I would like ...
3
votes
1answer
568 views

how to create Dataset after importing txt file

I would like to translate a imported txt file to Dataset. ...
0
votes
4answers
153 views

Using levels in MapIndexed

I am trying to use MapIndexed to manipulate a matrix of data but I am having trouble getting the levels parameter to work the way I would like. Suppose that my data ...
28
votes
3answers
1k views

Error changing Dataset using Part

Update It was a bug in the documentation of V10.0, this functionality was not implemented yet, and V10.1 changed the documentation, removing it. It's a pity, because it's a very useful operations, ...
112
votes
3answers
6k views

How to make use of Associations?

I have been curious about it for long. Now that Mathematica 10 arrives, I think it's time to ask the question: How the new Association data structure would be used ...
1
vote
0answers
156 views

What's a non-trivial Mathematica program involving conscious choice of stack vs. queue data structure?

In a typical computer science algorithms course, much attention is given to the discussion of queues vs. stacks as a data structure programmers need to consciously choose from to achieve algorithmic ...
44
votes
3answers
3k views

How can I add a column into a existing Dataset?

I'm very excited about the brand new Dataset function. I have played with it in Wolfram Cloud, and haven't figured out how can I add a new column into an existing <...
1
vote
0answers
94 views

Data structures sought for storing particular list information

I have a set of lists. These lists contain two dimensional coordinates of natural numbers. So a list can be ...