# Questions tagged [list-manipulation]

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

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### How to apply the Manipulate function on a 5D data set and visualize the data using ListContourPlot? [closed]

Say you have a data set with 5 columns and each column is defined by the variables theta, phi, x, y, z such that data(theta, phi, x, y, z). I would like to use the Manipulate function on this list and ...
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184 views

### Importing Specific Data from a Text File

I am quite new to Mathematica. I have a text file that upon importing has a repetitive structure with characters included. I need to extract only the following in numbers only (no letters, dash lines, ...
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211 views

### How to tally a list of lists only by considering the first element of the sub list

We need to Tally a list of lists only by considering the first element of the sub lists and then sort the resulting list. As a simple example consider ...
• 159
141 views

### How to implement this zip function? zip[g,{f[{a,b}],f[{c,d}]}] to f[{g[{a,c}],g[{b,d}]}]

I have a function that returns an expression in the form f[{a,b}], and I use this function twice and assemble the expression ...
241 views

### Select elements from a list based on alphabetical order criteria

I have this code to generate the anagrams for a 6 letters word: ...
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### How to sum over Slot inside MapThread

I am trying to do simple operations with several lists. In this context, I was wondering if a sum over Slot is possible inside ...
• 1,897
49 views

### How can I access subsets in manageable chunks?

I have a large subset (as an example). subset = Subsets[Range[8000], {2}] I cannot evaluate this as I don't have enough space. So the question is how can I access ...
• 723
163 views

### How can we arrange data for ListLinePlot? [duplicate]

I have this data ...
• 4,739
54 views

### Build 2D lists of functions and variables in different combinations

Can someone give examples on how to build 2D Lists of function and expressions by the given vectors? I have the following: V1={a,b,c}; V2={1,2,3}; V3={x1,x2,x3}; ...
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### How to convert the form of a solution from solve {x -> 1, y -> 1, z -> Sqrt[2]} into a list form {1, 1, Sqrt[2]}? [closed]

How to convert the form of a solution from solve as follows: {x -> 1, y -> 1, z -> Sqrt[2]} into a list form ...
• 4,884
180 views

### How to select right triangles and non right triangles given their coordinates

I have a list of triangle coordinates in 2D-space: ...
• 1,265
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### How to convert RowBoxes into list of math expressions?

I have following RowBox which represents Step By Step solution of undefined integral ...
76 views

### Flattening nested data generated in a table

The data in the following is structured like this $\{\cdot,\{\cdot,\cdot\}\}$, but I need it like this $\{\cdot,\cdot,\cdot\}$. How do I do this? ...
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### Extracting coefficients from a list of expressions

I have a list of the form, ...
• 1,533
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### JacobianMatrix function flattens input in column order

The JacobianMatrix function appears to flatten its input in column order. Both of the following queries (Wolfram Alpha syntax) give the same result: Q1: "JacobianMatrix of {{a_1+a_2, a_1+ a_2, ...
98 views

### How to generate an array with specific conditions?

To randomly generate an array of 10 non-negative integers with a mean of 3 and a variance of 2. ...
• 4,884
48 views

### Syntax regarding Manipulate plot with multiple functions

I am facing the following issue; I have the solution of a ParametricNDSolveValue and would like to plot several solutions with varying parameter in the same Manipulate to see qualitative differences. ...
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323 views

### Get cumulative sums in a list without using a for loop [closed]

I want a list of the kind list = {a,a+b,a+b+c} for list plotting. The quantities of the list come from a function. Let us say this is ...
• 411
81 views

### Find disjoint subsets and their union is {1...9}

I have such a list sets = Select[IntegerDigits /@ (Range[Floor@Sqrt@987654321]^2), DuplicateFreeQ@# && FreeQ[#, 0] &] I want to pick all subsets of ...
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39 views

### Writing list as disjoint union of input lists

Suppose I have two lists, s1={{1,2,3},{3,1,2},{3,1,2},{2,3,1},{3,2,1},{1,3,2}} and ...
• 101
1 vote
34 views

### Efficient chain rule implementation

(there is a fair amount of context here) I am implementing a generalized chain rule to do some work, say for order 3 in derivatives ($\partial_i = \partial/\partial x_i$): \begin{align} \partial_i \...
• 669
519 views

### Fill a matrix with randomly placed elements that are a certain distance apart

Problem statement I want to populate a matrix of points with randomly placed elements, here denoted as x. In all matrix rows there must be an equal number of x-...
• 82.6k
377 views

### Combining duplicate elements in a list

I have a list of the form, mylist = {{0.1, 1.2},{0.3, 2.1},{0.1, 0.5},{0.4, 0.4},{0.4, 0.1},{0.1, 1.6}} I would like to create a function, ...
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56 views

### How to use FoldList for matrix multiplication?

I'm trying to use FoldList to create successive matrices that depend on a changing parameter n, so the transition matrices are ...
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170 views

### How could I speed up this tensor product?

I have to take tensor products of lists of tensors and I want to include the possibility of tensors whose components have high working precision. The tensors are all totally symmetric, so the first ...
• 669
284 views

### How can I find all the different ways to group integer numbers from 1 to 10 into 3 lists?

(Unfortunately, I couldn't change the bounty message. By n above I meant the number of sublists.) How can I group a list of integers from 1 to 10 into 3 sublists of ...
• 723
1 vote
54 views

### How to convert a list of polynomials with different degrees into a list of lists?

I asked a question about converting a polynomial into a list. Now I have a list of polynomials. For example, ...
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313 views

### How to convert a polynomial into a list?

I have a list of polynomials. Each polynomial looks like: p[1, 2, 5] p[3, 6, 9] p[4, 7, 8] - 3 p[1, 2, 4] p[3, 6, 9] p[5, 7, 8] How to convert each of these ...
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### Reverse association and map through its values/keys

I suspect this could be done in a shorter and more readable code: Challenge: do it without Normal and Association. ...
• 21.4k
82 views

### Generating lists where new elements depend on the previous element

I am interested in using some type of list or table in-built Mathematica function to generate a list, where the elements of the new list not only depends on the input values of a previously defined ...
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333 views

### How to create sublists of a list based on the relation between their elements?

I have a large data set looking like this: ...
484 views

### How to remove extra brackets from a list?

I have a list which looks like the following: list1={{{a,b,c},{a1,b1,c1},{an, bn,cn}},{{f,j,k},{f1,j1,k1},{fn, jn,kn}}} And I need it to be as follows: ...
387 views

### Reconstruct list from its PositionIndex

Is there a more elegant or shorter way of reconstructing a list from its PositionIndex? The following I regard quite cumbersome: ...
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174 views

### Sort Column as a Row

I have a = {1, 2, 3, 10}; b= {2, 3, 4, 8}; t= Do[If[a[[i]]+b[[i]]>3,Print[a[[i]]],"No"],{i,1,4}]; 2 3 10 I need to get the result; t={2,3,10}
361 views

### Element-wise vector-matrix exponentiation

I would like to exponentiate the vector x = {x1,x2} element-wise with the non-square matrix A = {{1,0},{1,1},{0,1}} so that the ...
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### Isomorphic lists

Is there a function that outputs True if lists are isomorphic (there exists a rule that changes the first list into the second one and inverse of the rule changes ...
• 21.4k
173 views

### Generating permutations where no item appears in its original position [duplicate]

Given a Range[n] list, I need an algorithm that takes a permutation and output the next permutation. These permutations have the property that every item is ...
32 views

### Evaluating determinant with entries from ./ output

I generate 16 values (this is a differential equation shooting method problem) from this kind of evaluation, y41 = Evaluate[y4[tf1] /. torsolve4]; When I use them in Det[], it does not work because ...
48 views

### How to quickly join in the following way? [duplicate]

Consider the following table: tab = RandomReal[{0, 1}, {10, 3}]; subsets=Subsets[tab, {2}]; How to quickly reduce subsets to a ...
• 5,927
254 views

### How to quickly join in the following way?

Consider the following table: tab = RandomReal[{0, 1}, {10, 3}]; subsets=Subsets[tab, {2}]; How to quickly reduce subsets to a ...
• 5,927
177 views

### Use sequence-functions to find certain sublists

I want to split a list of positive Integers into sublists whose ascending elements differ by 1. list = {1, 0, 1, 0, 1, 4, 5, 6, 5, 8, 1, 2}; This can be done ...
• 82.6k
107 views

### Count consecutive repeated patterns in a list [closed]

Given a list such as: ...
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127 views

### Tally elements in a list of matrices up to an overall sign

I have a list of matrices like the following one with 6 elements: ...
• 115
1 vote
109 views

### Map array of functions

What is the most elegant way of mapping an array of functions to an array of arguments of the same length? In practice I want to map {f1,f2,f3} and ...
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277 views

### Searching for a list in a list

I want to see if a specific list is part of another list and get either True or False. As an example: ...
52 views

### Do one calculation over the whole list [closed]

I am trying to calculate the numerical residue of the function, but I want to perform it at the whole list and as a return. For example, let's take ...
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18 views

### How to remove part of a plot range between the data? [duplicate]

Is there a way to manipulate a plot range to be non continuous? I mean, I have some data that goes from x=18;;25 and then x=45;;50. I want to plot the in the same ListPlot, but if I do so there's a ...
1 vote
57 views

### Multiple assignments of items of a list [closed]

Suppose to have a list of items and two lists of indexes that are parametric and for example are: l={2,3,5,7,11,13,17} i1={3,4,7} i2={4,7,3} I need a clever code ...
125 views

### DuplicateFreeQ VS UnsameQ

What is the exact difference between DuplicateFreeQ @ arr and UnsameQ @@ arr ? I checked on many examples and found no ...
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1 vote