Questions on the manipulation of List objects in Mathematica, and the functions used for these manipulations.

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0
votes
0answers
57 views

Time series of a point using ImageFeatureTrack

This question regards tracking, however it is more about writing efficiency in mathematica compared to other programming softwares. I get the tracking of a point between two movie frames by: ...
5
votes
1answer
81 views

Longest and Shortest won't work in ReplaceList?

I'm trying to make a pattern that's easy to preceive by human but hard to write out by Mathematica when I came across this problem. (Check the original problem here) Let's check this simple case: I'...
2
votes
1answer
42 views

Diagonal part of product of matrices

I am trying to find the best way to compute only the diagonal part of a product of two (or three) matrices. I tried two different approaches: computing the standard matrix product and then extracting ...
3
votes
2answers
332 views

Maximum brightness of two gray scale images

I am using the answer of bill s in Greater operator should give greater element. Here he showed the example: ...
0
votes
0answers
42 views

More efficient way of filling in a specific entry in a list of lists [duplicate]

"coords" is a list of coordinates in the 2D plane ordered in a specific way, with the 3rd (z-axis) positions left empty to be filled in with specific values, like temperature or concentration at the ...
3
votes
1answer
117 views

How to Find out the Recurring Period by Pattern Matching?

Note: It's not hard to solve this problem AT ALL, so please, try to explain how to use PATTERN MATCHING instead of how to find out the recurring period. We can easily extract real digits from a ...
0
votes
2answers
57 views

Random Matrix with criteria

I want to construct $k$ lists $M$ of positions $(i,j)$ for a matrix $X$ of size $n\times m$, where all entries are "painted" with "white" color. The distribution of such a list $M$ must obey the ...
0
votes
2answers
70 views
0
votes
0answers
41 views

output has a term uncomputed

I am trying to sum the all numbers in each row of matrix and divide them by the max value of the row. My output has the following terms that has not been computed yet (example, the second element in ...
1
vote
1answer
67 views

How to do abstract matrix operation?

In this simple example, I have 2 lists, each of which contains 3 matrices。 $J$ here is also a matrix with the same dimension. What I want is $aJc+bJ(b+c)$, but if I use dot product, the result is as ...
2
votes
2answers
58 views

How to transform the $y$ values in a list of $(x,y)$ pairs [duplicate]

How can I transform data = {{1, 0}, {0, 1}, {1, 1}} to {{1, f[0]}, {0, f[1]}, {1, f[1]}} This is similar to ...
0
votes
1answer
31 views

How to pair elements of a nestlist? [duplicate]

I have a this list for example expdata={{49, 50, 51, 52, 53, 54},{0,3,5,2,0,1}} and I want to rearrange it like this ...
1
vote
1answer
33 views

Converting a list of lists of indices into a sparse matrix of ones and zeros

I have data formatted like {{a,b},{c,d},{e,f}} where each entry is an integer. I need to turn this in to a sparse array with entries ...
2
votes
1answer
91 views

Python Convolve2D functionality in Mathematica

I am new to mathematica. I am looking for an alternative for scipy.signal.convolve2d. I did find functions like ListConvolve, ...
0
votes
1answer
59 views

How can I get the differences of all elements of list? [duplicate]

I want to get the difference of all elements of a list for example: $L=\{1,2,3,4,5,6\}$ for any $i$ and $j$ $\in L$ return the differences, for example for the first element $1$ we get the difference ...
0
votes
0answers
60 views

Henon Map Equation Trekker

I am trying to make an Equation Trekker for the Henon map in the following way: ...
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
6
votes
2answers
97 views

Query or MapAt ragged associations or ignoring Missing values

Related to this question, can functions be mapped to named Keys in ragged lists of Associations? ...
6
votes
2answers
332 views

Cross product between two lists of vectors

I'm trying to create a function that does the cross product between two lists of the same dimensions, element by element. Each entry of the list is a 3D vector. Something like this: ...
1
vote
0answers
27 views

Make a .C3D file in Mathematica

I have two different groups of points in an excel file, which are captured by two different cameras from two different angles (Motion Capture Process). These points are extracted by using markers on a ...
0
votes
0answers
39 views

Removing 1 from FactorInteger

I am trying to remove the factor of 1 out of FactorInteger, so that I can search though numbers with common factors easier. Here is what I have already: For[n = 0, n < 10, n++; b = FactorInteger[...
1
vote
0answers
44 views

Remove columns basing on binary sequence

Possibly it is duplicate, still I could not find here elegant way to remove matrix columns basing on binary sequence. i.e. if I apply {1,1,0,0,1,0,1} to matrix it should delete columns 3,4 and 6.
0
votes
2answers
101 views

How to generate a Markov Matrix efficiently

A Markov Matrix is a square matrix,which have two features: All elements great than or equal to $0$(But I hope all element great than or equal to $0.1$) All the columns add up to $1$ I have a ...
1
vote
2answers
63 views

Dividing a list into more, smaller, lists [closed]

If I have the list {3,5,4,2}, is there a way to divide this list into smaller lists of the form {3},{5},{4},{2}?
0
votes
2answers
52 views

Nested lists replacing of elements [closed]

I have a list of the form SpecialCycle12={{{1, 2, 0, 0, 0, 0, 0}}, {{3, 2, 1, 0, 0, 0, 0}}}` And the list ...
0
votes
2answers
46 views

Can you unpack a list of values into variables in a With expression?

For instance, if I am trying to draw a graph with 5 vertices labeled a through e, and I want to draw edges connecting a and b, a and c, a and d, a and e, b and c, b and d, and c and e, I would run the ...
8
votes
4answers
165 views

Replacing elements in lists of a nested list

I have the following nested list ...
0
votes
0answers
51 views

How to take a list and build sets of 2 elements without duplicates?

I am new to Mathematica so the answer to this question is probably easy. I have a list of 2D-points in the form {{x1, y1}, {x2, y2}, ...} Then I have a function that will take two points and test ...
5
votes
4answers
175 views

Efficient way to compute a complement while respecting multiplicities [duplicate]

Suppose I have list2 which is a subset of list1. I want to get a res by deleting an element ...
3
votes
0answers
64 views

ArrayPad with vectors [closed]

I would like to pad a nested list like M = {{{a, b}, {c, d}}, {{e, f}, {g, h}}} with some constant "vector", e.g. {0, 0}. ...
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 ...
3
votes
2answers
100 views

Inverse action of Thread

I cannot find the original post now, but I'm quite sure that there's an amazing post teaching us how to do Thread on ragged lists. but my problem is how to inverse ...
20
votes
2answers
598 views

Mysterious behaviour of Pick

As everyone knows, Pick can do amazing things, The most fascinating phenomenon is that it can pick though all sorts of lists: The basic & pattern matching: <...
1
vote
1answer
69 views

Creating a Dynamic Time Index Slider for List Animate Plot

I am trying to create an animation using ListPlot, which has worked, but I want to be able to see how time is changing (i.e. its dynamic value) as the animation runs. Here is my normal List Plot ...
2
votes
1answer
84 views

How to define the following matrix

How to define the following matrix in Mathematica? $$A(n) = \begin{pmatrix} B_{1} & B_{2} & \cdots & B_{n} & 1 \\ B_{n} & B_{1} & \cdots & B_{n-1} &1 \\ \...
0
votes
1answer
53 views

Color a list of 2D points continuously

I have a list of 3-tuples. First 2 positions are coordinates in $R^2$, the third specifies concentration of a chemical at that point, which I want to render in color. Here's what the list looks like: ...
4
votes
2answers
109 views

Strange Manipulate behavior

Running the following code and pressing the play button under b will input -2147483648 in b. ...
1
vote
2answers
82 views

Interpolating initial conditions of orbits

I have a data file containing the $(x,y,p_x,p_y)$ initial conditions of two-dimensional orbits. Let's plot them on the $(x,y)$ plane. ...
1
vote
1answer
71 views

Predicting the initial conditions of orbits inside a closed curve

I have a data file containing the four orbital element $(x,y,p_x,p_y)$ of a two-dimensional closed loop orbit. Note that the exact implicit equation of the orbit is not known. The plot of the 2D ...
1
vote
2answers
53 views

Passing each element of a list as an argument to a single parameter function [closed]

Consider a single parameter function: g[w_] := w^2 +1; Consider a list: slist= Range[0, 100, 1]; Now when I apply function ...
3
votes
5answers
216 views

How to select elements from a list of pairs based on 2nd element of the pair [closed]

I have a large list of arrays of the following form ...
5
votes
3answers
70 views

Using select in a nested list [closed]

I have a nested list of the following form ...
1
vote
0answers
32 views

Arrange of several files

I am struggling to import my data. There are 400 files in CSV format with names organised by date like: Table1_20111003_YYYY_MM_DD_0000.dat. In each file over 20 colums and 86400 rows (seconds of ...
4
votes
5answers
206 views

Transforming a list of the form {{{x, y}, z}, … } into the form {{x, y, z}, … } [duplicate]

This should be a fairly simple question, but I can't figure out how to do it. I have a list of points of the following form: ...
1
vote
2answers
56 views

Not able to apply Scan in place of For loop [closed]

I have been advised to avoid procedural loops and use other functions like Scan,NestList, FoldList, NestWhileList, Inner and Outer. My worry is that if I have a need in which certain critical ...
9
votes
11answers
1k views

Riffle but not quite

Given the two lists below, is there an in-built command or otherwise neat way of accomplishing the desired output. ...
1
vote
1answer
81 views

Creating sublists [duplicate]

I got this example in Mathematica references. v = ToExpression["a" <> ToString[#]] & /@ Range[1,44] Could someone explain to me the function of the ...
1
vote
1answer
60 views

Create a table indexed form a list giving a the index specifications

I need to create a table indexed form a list. e.g.: list={{i, 3}, {j, 4}}; would give the table Table[..., {i,3}, {j,4}]; ...