# Tagged Questions

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

320 views

### How to remove a line of a matrix if not all elements are numeric?

I have a matrix a n columns and m lines. I'd like to efficiently remove the lines that are not entirely composed of numeric ...
45 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? ...
308 views

### Algorithm to generate a certain matrix

I am looking for a convenient way to generate a matrix of the following symmetric form (numbers could also run from -3 to +3 or just from -1 to +1): Tips, anybody?
295 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: ...
21 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 ...
38 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[...
87 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 ...
42 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.
94 views

### Union sorting after ignoring some digits

I have a list with its bellow elements: {-0.7071067811865476, -0.7071067811865475, 0.7071067811865475, 0.7071067811865476} If I use ...
50 views

### Nested lists replacing of elements

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 ...
57 views

### Dividing a list into more, smaller, lists [on hold]

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}?
152 views

### Replacing elements in lists of a nested list

I have the following nested list ...
42 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 ...
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 ...
170 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 ...
61 views

### ArrayPad with vectors [on hold]

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}. ...
512 views

### Mysterious behaviour of Pick

As everyone knows, Pick can do amazing things, The most facinating phenomenon is that it can pick though all sorts of lists: The basic & pattern matching: <...
78 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 ...
90 views

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 ...
105 views

### Strange Manipulate behavior

Running the following code and pressing the play button under b will input -2147483648 in b. ...
59 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 ...
79 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 \\ \...
80 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. ...
47 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: ...
68 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 ...
51 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 ...
210 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 ...
134 views

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67 views

### Using select in a nested list [on hold]

I have a nested list of the following form ...
80 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 ...
31 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 ...
201 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: ...
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. ...
54 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 ...
59 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}]; ...
93 views

### Group matrix values by column [closed]

Original Question: I have a list {{a, 1}, {b, 3}, {c, 1}, {d, 2}, {e, 3}}. I want to be able to group the the first number in each pair that has the same second ...
194 views

### Selection of points based on position

I have a series of points, for example: points = {{0, 0}, {1, 3}, {2.5, 2.5}, {4, 4}, {6, 6}}; I want to join all points successively unless, for example, the y-...
79 views

### Animating Differential Equations [closed]

I was tasked with creating a 3D animation in Mathematica, which aims to describe the movement of a football through space as it's kicked. There are several differential equations regarding this matter ...
44 views

### Rotating the nested lists of a list [closed]

I have a nested list of the form List1 = {{1},{2},{3},{4},{5},{6}} I want to apply RotateRight to each of the elements in ...
51 views

### Putting the elements of a list inside another list

I have the list list1 = {1, 3, 4, 5, 6} and want to put the elements of this list inside a list of 0's, ...
102 views

### Changing the order of elements in a list

I have a list of the form list1 = {1, 3, 4, 2, 5, 6} and I would like to replace each of the elements in the position of represented by the previous number in the ...
53 views

### Convolution with modified indices

I want to perform convolution for a sequence but instead of having the indices cycle from the ends periodically, I want to apply a function, specifically Abs, to ...
151 views

### Selecting points inside a closed curve

Let's create a rather dense grid of initial conditions ...
44 views

### Mapping AssociationThread over list with repeating keys [closed]

I have two lists. One with the same repeating four keys and the other with unique values. Both are the same length. I want to Associate the first list with the second list. So if that if the 5th ...
27 views

### Splitting a list into sublists with different sizes [duplicate]

I have the list {7, 8, 9, 10, 11, 12, 13, 14} and would like to split it into a list of size 2, a list of size 3, and covert the remaining element into singleton ...
145 views

In the following example Nearest finds the nearest values between list1 and list2 and ...
913 views

### Combining values in one column (or part) when values in another column (or part) match

Consider the following: ...
758 views

### Using Partition to allow sublists of different lengths

As a minimal example, suppose I have a list of the integers from 1 to 25. Suppose I want to use Partition to partition the list into sublists of length 10 but ...
104 views

### Calculating density of states from lists of momentum/energy data

I am trying to calculate the density of states for a 2D system given certain band structure data organized in a specific format. Below is an example of my procedure: Beginning with a simple 2 x 2 ...