Questions on the sorting/ordering functions of Mathematica (Sort, SortBy, Ordering, etc.).

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0
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2answers
61 views

Large matrix: Finding eigenvalues and ordering it with respec to the highest coefficient of its eigenvectors

I have a 900x900 matrix to diagonalize. After diagonalizing it, I have a table of eigenvalues and eigenvectors. For convenience, I start with 3x3 matrix. ...
0
votes
0answers
46 views

Mathematica, stop sorting my output! [on hold]

I'm trying to get some output from Mathematica / WolframAlpha, but it's coming out in a useless format. Mathematica is, for some reason, sorting my output. Below is the output from my function and ...
0
votes
0answers
38 views

Sorting Ordered List of Words by First Letter

I am trying to sort an ordered list of the most common Arabic words. I want to create sublists of words according to their first letter while maintaining the order of the original list. Here's an ...
-1
votes
0answers
25 views

How To Sort BarChart Data Based On the Selected Column

This sample code works fine for the category of StarData selected. What I would like to do is sort the data based on which BarChart is selected. ...
0
votes
1answer
79 views

Sorting matrices by their norms

I have a matrices A and their Norms(Matrices B). I want to rank Matrices A based on their Norms. From smallest to highest Norm
1
vote
1answer
50 views

Sorting Data by Differences between Columns

In Band Structure calculations one gets rather extensive data of Energy Values (Eigenvalues) and the associated Eigenvectors out of the solution of an Eigenequation of e.g. the form H.$\psi$=E.$\psi$. ...
2
votes
1answer
84 views

Double Sorting a Matrix

Say I have two matrices {{0, 1, 2, 2}, {2, 1, 0, 2}} and {{2, 1, 0, 2}, {2, 1, 2, 0}} I then sort by the first row ...
2
votes
1answer
155 views

How to sort eigenvalues?

I am trying to find Eigenvalues to a 12x12 Matrix ($H$) dependent on two variables $x$ and $y$. Later I want to do a 3D plot of one eigenvalue ($E$) over $x$ and $y$. An analytical solution is not ...
2
votes
1answer
66 views

Order of importing data from files

I have many text files numbered from 1 to 1 million in numerical order. Within each text file is 5 columns of data (TAB spaced) with many rows. I effectively want to take the minimum value from each ...
1
vote
0answers
28 views

How to customize the order of leaf labels in a dendrogram plot?

Take the following simple case as an example: Needs["HierarchicalClustering`"] SeedRandom[99]; Sort@RandomInteger[99, {10}] gives {2, 7, 22, 34, 42, 58, 60, ...
10
votes
3answers
344 views

Retaining and reusing a one-to-one mapping from a sort

Imagine I sort the elements of an array $Q$ by some means. Perhaps I sort strictly by the elements in the first column, perhaps I use SortBy[...] to sequentially sort by the elements in successive ...
4
votes
2answers
179 views

Sort by returning positions [duplicate]

How can I computationally efficiently sort a list so as to return the positions and not the actual values at those positions (which SortBy does)?
1
vote
3answers
339 views

Matching the order of a master list of lists from a random list of lists

Using Mathematica 9, I have 2 lists of lists one master with dimensions {300, 6}. The second is some random order but has the same first ...
0
votes
1answer
46 views

Applying multiple functions to a single column in a table

I've seen similar questions, but I'm having trouble applying solutions found there to my situation. My sorting function: ...
1
vote
1answer
55 views

Sorting the words of a phrase by defined variables/associations

Is it possible to change the word order of a phrase by creating a list of possible values/variables and using the Sort function? I want a specific word order always. $(a>b>c>d)$ But the ...
1
vote
2answers
219 views

Use of Sort with custom functions

As mentionned in the topic title, I try to apply my own sorting functions to a set of elements via the Sort command. I make here a quick presentation of the subject before. 1) Method We will ...
23
votes
4answers
4k views

Sort data after specific ordering (ascending/descending) in multiple columns

I have some data: data={{"a", 1, 1}, {"a", 1, 2}, {"a", 1, 3}, {"c", 2, 1}, {"b", 2, 2}, {"b", 2, 3}, {"c", 3, 1}, {"a", 3, 2}, {"a", 3, 3}} When I ...
3
votes
1answer
85 views

Plotting eigenvalues smoothly

I am trying to plot how the eigenvalues of a matrix change by changing a given a parameter t. Of course the ordering of the eigenvalues does not matter mathematically but it does when I want to make ...
6
votes
3answers
292 views
6
votes
3answers
1k views

How to plot several functions without jumping? (multiple eigenvalues of a system as functions of 2 parameters)

I've been working on this research problem for months with some success by no global/proper solution to the problem. So I have square, Hermitian matrices of various sizes ($8,20,38$ dimensions) with ...
2
votes
0answers
31 views

How to sort data as in Excel? [duplicate]

How to create a program in Mathematica to sort data (table with several variables) by different variable, by clicking the name of the variable, much like in Excel with freeze pane?
15
votes
4answers
522 views

Reproducing a ranking function that behaves like Excel's RANK

I tried to find a function or expression in Mathematica that produces the same output as the RANK function in Excel (see its description here), but unfortunately I ...
3
votes
2answers
86 views

Problem with Custom Sort/Split/Gather

Please help me Sort/Split/Gather/Group(by) a set of symbolic expressions! (extreme TL;DR at bottom) I have a set of symbols (which represent 2-vectors in a plane, ultimately) and I want to sort/...
2
votes
1answer
71 views

How to check a clockwise direction for a list of point [closed]

Suppose that we have a list of points and we need to order them in clockwise direction by starting from a special point. I implemented this code to order them but I need to detect if it is ordered in ...
21
votes
2answers
806 views

Ordering problem

Let's look at the following example. Ordering[{0, 20 Sqrt[5], 40 Sqrt[5], 20 Sqrt[5], 20 Sqrt[10]} // N] gives the right answer ...
9
votes
3answers
333 views

GatherBy/SplitBy and Sort a list

So let's say I want to group a list of points based on their distance from the origin. I would do something like: ...
3
votes
2answers
91 views

Role of Accuracy in numerical evaluations, SplitBy vs GatherBy

This is a follow-up question to this question. I generated a list by substituting the results of a solve[] routine and set: ...
0
votes
1answer
65 views

Can't sort my list numerically for larger numbers than 10 e.g. 1,10,100,2 [duplicate]

I want my files names in real numerical order so 1,2,3,10,12. However it is currently putting them in order like so: 1,10,12,2,3 Input: ...
2
votes
1answer
244 views

What is wrong with my user-defined ordering function?

I've defined ordering function: myOrderingFunction[arg1_, arg2_] which always return True or ...
4
votes
3answers
107 views

Change Contour Plot Overlap Ordering

I have a contour plot for which I have selected a finite set of contours. However, the contours overlap in some places and I would like to reverse the order in which they are drawn. In other words,...
3
votes
0answers
296 views

Negative power instead of fraction [duplicate]

Solve returns a solution in the form {{ x -> y / a^2 + y^2 / a^7 }}. Since I want to process the input (with another program) in terms of Laurent polynomials, I ...
1
vote
0answers
62 views

Finding correct combination of functions

I am trying to write code where I have an array $S$ or numbers in any order [5,4,2,1,....] Then I have a specific set of functions that I can write. ...
20
votes
4answers
423 views

Unexpected result {“.a”, “co”, “.m”} from Sort[{“.m”, “.a”, “co”}]

I came across the following situation: Evaluating Sort[{".m", ".a", "co"}] Results in {".a", "co", ".m"} I wondering: ...
0
votes
1answer
64 views

Unexpected result from Sort with symbolic values

I think Sort should be able to sort symbolic values that are reducible to numerical values, but this example seems to get a wrong answer (here is a simplified ...
2
votes
2answers
56 views
5
votes
1answer
109 views

How to order a list to match the order of another list?

How can I order a list to match the order of anoter list ? For example: Suppose I have the lists x = {3, 1, 5, 7} and ...
3
votes
1answer
78 views

SortBy behaving strangely with missing data

I'm trying to create a grid that shows the largest data value from a list. What I have mostly works- the problem comes when there is missing data. You can't really tell here, but all of the ...
11
votes
5answers
458 views

How to sort list of mixed types of elements with each type a specified canonical order?

For example, here is a list {{1, "u"}, {6, "d"}, {3, "u"}, {4, "d"}, {2, "u"}, {5, "u"}, {3, "d"}, {1, "d"}, {4, "u"}, {2, "d"}, {5, "d"}, {6, "u"}} The ...
7
votes
2answers
314 views

Wolfram Language symbols by their Ranks

I'd like to get the top 50, the bottom 50 and an ordered list of all Wolfram Language symbols based on their "Ranks". With ...
0
votes
1answer
52 views

Sorting in descending order of list [closed]

I have a list m = {{a, 20}, {b, 10}, {c, 50}, {d, 5}, {e, 100}} and I want to apply Sort on this in descending order on ...
3
votes
2answers
228 views

Exercise using Sort

I have to order the following list according to the sum of the powers of each element of the list, using the function Sort. ...
4
votes
2answers
118 views

Sorting and keeping the main format of list numbers [duplicate]

I have a list with these elements: list={1/2 (1 + Sqrt[5]), 1, 1, 1/2 (1 - Sqrt[5]), 0}; I want to sort them with ...
1
vote
2answers
126 views

How do I use Subgraph to sample the $n$ vertices of a graph with the greatest connectivity?

Let $G$ be an arbitrary graph with some number of vertices $||V||$ and some number of edges $||E||$. We can use Subgraph to generate, well, a subgraph of ...
7
votes
2answers
440 views

Position function not always returning an answer even with no apparent problems

I'm having some problems with Position. Sometimes it will give an empty list instead of the actual position of the element I am looking for when that element is ...
1
vote
3answers
152 views

Complement[] changes order of elements?

Consider this example: Complement[{a, y, c, d, e}, {a, c}, {d}] (*{e, y}*) However, I was expecting the result to be: ...
2
votes
1answer
61 views

Sort a list of derivatives

I have a list of variables, both constant and functions of an independent variable, including derivatives. I'd like to sort these by the variable name, rather than the derivative order. For example, ...
1
vote
1answer
42 views

Reverse order in evaluated list

I solve the following set of ODE and plot solution of S1 vs k2 (Figure 1). ...
5
votes
1answer
837 views

How to implement Kemeny-Young method? (rank aggregation problem)

Prehistory I am trying to make some statistical analysis of some experimental data, arises from measurements made ​​on an ordinal scale. I faced with the problem of rank aggregation: to get from ...