# Tagged Questions

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

168 views

### Missing control for depth of Inner

Working on a mechanics problem, I stumbled on something peculiar: Since Inner is a generalisation of Dot, it changes its ...
225 views

### Recursive functions taking list arguments

I wish to create a function that takes lists (e.g. {plus,plus,minus,0,minus,plus}) and uses the input list to calculate a corresponding value using a set of ...
75 views

### Choosing a List as VertexWeight for a TreeGraph

I would like to map every vertex of my TreeGraph to an List. ...
53 views

### How to add a part of a list to a function?

I want to be able to add a specific portion of a list to a part of a function but this fucntion intakes 6 variables where as the list is of example: ...
100 views

### Finding an idiomatic way to express a system of linear equations

I have an $n$ x $n$ matrix $T$, where $t_{ij}$ is the element at the $i\,$th row and $j\,$th column, and unknowns $x_i$, $1\leq i \leq n$, where $$x_{n} = 1$$ $$x_{n-1} = 0$$ x_i = \sum_{1\leq j \...
288 views

### Polynomial with alternating sign coefficients from the odd degree terms of a Truncated Power Series

I'm trying to make a function that will take any truncated power series I give it, strip away all the even degree terms, then change the sign of the coefficients of every other term. So that we have a ...
84 views

### Generating increasingly longer lists from a single list

I start with an array such as {{1,1},{0,1},{-1,1}}. (1) I want to create an array from this which replaces each array inside the array with 3 new arrays, one ...
180 views

### Transform a rule to a list of rules

How can this rule a -> {1, 2, 3} be transformed into this {a -> 1, a -> 2, a -> 3} by way of a function? ...
254 views

### Complicated list slicing

Say I have a list with the structure list = {{1, {x1, y1, z1}}, {2, {x2, y2, z2}}, {3, {x3, y3, z3}}, ...} I would like to slice it such that I end up with <...
106 views

### Using List/Histogram Data As A Weighted Function?

I have a list of data points that I would like to use as a weighted function. The data represents the number of particles within a bin of a particle distribution. Ultimately I would like to multiply ...
720 views

### Enumerating tuples from a larger space such that all pairs of values are present at least once

I am trying to write a function that will accept a list of N lists and returns a list of N-tuples that represent all pairs of values from the original N lists at least once. To illustrate with an ...
164 views

### Easy way to perform multiplication of two 2x2 matrices, that contain list elements?

I have two 2x2 matrices, which elements are lists (so overall structure can be complicated). I need to perform matrix multiplication of these 2x2 matrices as if the elements didn't have its inner ...
631 views

### What is the best way to draw a shaded table?

I'm trying to format a raster-style table with row and column headings and in which each cell is shaded according to the value in the cell, and the value of the cell is displayed in as text in a ...
186 views

### Get the position of the right interval

I have a list of intervals: Intervals = {{0, 1}, {1, 2}, {2, 3}, {3, 4}, {4, 5}, {5, 6}} and a list of measurements: ...
883 views

### Exclude data from a list

Let's create some random sample data data = Table[{RandomReal[{-10, 10}], RandomReal[{-10, 10}]}, {i, 1, 300}]; Then we plot them using ...
265 views

### Using 0 to create new columns in a list with Part

I just discovered a nice way to create intermediary columns in a list, and I would like to know if I can have some problem with it. It Works like this: Imagine I have this list, 5x3: ...
492 views

### How to exclude some indices in defining Table?

Suppose I define a table using Table[n, {n, -n0, n0}] (where n0 is some positive integer) but I want n not to take the value <...
413 views

### Compare 2 lists

I want to compare 2 lists. One is very large and I need to compare many times. Lets say Length[list1] I need to know how many times list1 occures in list2. Eg. list1={1, 0}, list2={1, 0, 1, 0, 1, 1} ...
127 views

### Lists of integers coprime to another list

I have two lists of integers. The first, p, is a list of primes (for example, {2,3,5,7}). The second is a list ...
171 views

### Eliminate symbols from Lists

I'm working with a list of roots of a 3rd order polynomial family, so i get a list this way: ...
115 views

### Manipulate list in function

I have some problems with lists and functions. Basically I just want to cut all entries from the right side, which contain 2. ({2,1,2} should become {2,1}) ...
522 views

### Efficient Indexed Sort

Suppose I have a preference for animals given by: orderOfAnimals = {"dogs", "cats", "fish", "elephants", "giraffe", "hamsters", "poodles"}; I'm given many data ...
234 views

...
102 views

### How to express “if any component in a vector satisfies that …” in Mathematica

For example, l is a list of vectors. I need to delete from l all the vectors with any component larger than 1. How should I do ...
35 views

### MapThread with incompatible length (How to Map twice in the same line)

l and b are two lists of vectors with different length. I need the list of vectors that is constructed by adding each member of <...
586 views

### Removing all values from a list that satisfy a given condition

Suppose I have a list, list = Table[{n}, {n, 1, 5}] (* list = {{1},{2},{3},{4},{5}} *) and I want to remove all values from this list that are greater than 3, so ...
272 views

### Error: in the part assignment is not a symbol [duplicate]

I am trying to set part of a Doubly-indexed list aInitialPopulation to cNumHeg. Specifically I am trying to set the 3rd part of the list aInitialPopulatiom[[cNodeNumber]] to cNumHeg. My (attempted) ...
129 views

### Distributing identifiers

I have a list that looks like this: {{"a",},{2010,0},{2011,10},{2012,27},{"b",},{2011,11},{2012,66},{"c",},{2010,19},{2011,20},{2012,}} I want to turn it into: <...
90 views

### Finding duplicates in a list [duplicate]

I have a list of integer, and I want to know if the list contains any duplicates. My code is working, but I feel there is a more straightforward way of doing this ...
122 views

### Excluding cases from Map

I'm doing operations of the form: PowerMod[#, -1, 126]+# & /@ Range[1, 125] When a number is not invertible, I don't want it to be included in the result set....
136 views

### How to sum values in the list that belongs to same week

I need to sum values that belongs to same week. For example, I have the list x with one column and n rows. Format: ...
291 views

### Finding the first position in a list that is over a certain value

Let's say I have the following list: L = {2,4,6,8,10} How can I get Mathematica to find the index position of the first value in the list that is over 4 (6 in ...
85 views

### How to manipulate one column of a table using the value in another column

Let's imagine I have the following table structure data = {{a, b}, {c, d}, {e, f}}; and I want to transform it into the following table ...
218 views

### A rule replacement problem: list -> list

Suppose I have a vector function f[x_] := {x[[1]]^2 - x[[2]]^2, Sin[x[[1]]] + Cos[x[[2]]]}; Then I want to make a list of gradients at some values: ...
133 views

### replace two elements in a list with the sum of those two elements?

I have a list: G[3] = {2, 4, 2, 4, 2, 4, 2, 4, 2, 4} (there's a 3 in there for the 3rd Prime) Recursively defined by: ...
111 views

### Modifying a list of matrices with conditional statement

I have a list of around 100 matrices, that looks like this ...
459 views

### Computing a map between two lists

What I want is a little difficult to explain. So I try to it with an example. I have 2 lists, each of which has $(n-1)^2$ elements. Each element is an integers between 0 and $n-1$, inclusive. For ...
156 views

### Histogram from a list of matrices

I have a list of around 100 matrices, that looks like this ...
96 views

### How to form a variable from matrix elements

I have matrix with n rows and 2 columns, say m = {{x11, y12}, {x21, y22}, ..., {xn1, yn2}. Now, I want to form three new variables for example: ...
345 views

### How to delete certain unwanted elements from an array

Suppose I have an array like so array1 = {{Null,2,3,4,5}, {a,b,c,Null,e}, {w,x,Null,y,z}} Is there some way to selectively remove any element I ...
60 views

### Multiway Systems Rules List Management

I'm working with a multiway system and I have a number of different mutation rule lists. I need an efficient way of managing which rule lists I apply. Here is the basic multiway system code that I'm ...
156 views

### Symbolic combinations

If I have 3 lists: {a,a},{b,b},{c,c}, then the desired output is ...
73 views

### Exporting mixed data of matrices and vectors / lists

thank you for reading my question. I have a problem trying to export mixed data from Mathematica. I have different matrices and vectors, which should be combined to a output file. Here a minimal-...
205 views

### Making a list of rules from the list of elements

Starting from the list: {f[q1, q2], f[q3, q4], g[q1], g[q2, q3, q4], d[k1 - q1], d[k2 - q2 - q3 -q4]} I would like to get the result: ...
206 views

### Pare down list recursively

What is the best way to pare down a list whereby the $n$th number is removed from the list recursively? This ...
120 views

### How to create a complex variable from dated list values

Can anyone help me to construct a variable "PI" from values of variable x. Variable x represents a group of two time series rj and ri on equal dates(joined two dated lists with states).Variable x have ...
481 views

### How to extract a part of matrix satisfying certain condition(s)

I have a following matrix ...
3k views

### Selecting every n-th element from a list

I have a list: data = {4, 5, 7, 8, 9, 5, 3, 2, 1, 2, 13, 12}; I want to take those elements in the list which are located at equal distances, say, every third ...