Questions tagged [list-manipulation]

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

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0
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0answers
6 views

Passing list into another list

Suppose I have a zero matrix Amat and a list of values ltest that contains the values of the matrix ...
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1answer
32 views

getting keys of an Association

Suppose you have an association of the type: ...
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2answers
71 views

From index-based `Table` with different levels to `Map`-based operations?

Toy example: ...
4
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2answers
66 views

xyz SplitBy y then Drop y for ListLinePlot

I'd like a more efficient way of doing the following: I have xyz data in the form of MyList for which I'd like to plot z as a function of x, split by y. ...
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2answers
62 views

Combining lists of a factors with multiplicity

I want to combine factorizations of integers (in the form output by FactorInteger, that is a list of factors with multiplicities) into the factorization of the ...
4
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2answers
65 views

How to extract subsets in a list based on the largest element in the subset?

For example, if i have a list as following: ...
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1answer
65 views

Get element of three list combine one by one

I have the following: ...
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1answer
38 views
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3answers
98 views

List manipulation: Find duplicates with respect to symmetry in sublists

I have the following list ...
2
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1answer
63 views

How can I calculate the Allan Variance of a list of Data?

I have a list with over 10.000 elements of data. Now I wanna calculate the Allan Variance of this Measurement. The Allan Variance is defined as following: $$\sigma_y^2(\tau)=\frac1{2\tau^2}\langle(x_{...
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0answers
21 views

Parallelizing ToExpression on a list [closed]

I have a list {"a+b+c","asd+rhy+bgf","at+aw+aw"}. What should I use to make ToExpression ...
3
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5answers
70 views

I want to Prepend the Row Number of the Matrix to all Elements within that row

I have a matrix of nested lists that looks like this: ...
4
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3answers
155 views

generating lists of integers with constraint

Suppose you have the list $a=(k_1,k_2,k_3, \dots, k_N)$ such that $k_{i}\; (i=1,\ldots, N)$ are non negative integers. How can you get all the lists that satisfy the constraint $\sum_{i=1}^{N} k_{i}=M$...
1
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1answer
39 views

list elements as indices

I have the list R: ...
11
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9answers
932 views

list-array construction

I want to create the list ix={1,1,1,1,2,2,2,2,3,3,3,3,4,4,4,4} I can do ...
2
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1answer
201 views

How can I condense this code?

Here is part of a code I wrote: ...
2
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2answers
176 views

Delete a range of elements from a list [closed]

If I have a list of 100 integers, say {1,2...100}, and I wished to delete all elements that are greater than a random integer $n$, what command should I use for ...
5
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1answer
110 views

ReplacePart to substitute a row in a Matrix

I have a very large n x n matrix from which I want to take a row i from and substitute every element with 0. When I try the below command however, the ith row is not replaced by a list of n zeros but ...
3
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2answers
134 views

Replacing a random ith row and column from a matrix

Currently I am trying to delete a randomly-chosen $i^{th}$ row and column from a square $n \times n$ matrix $A$. So far I come up with the following code: ...
0
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0answers
58 views

Correct way to format numbers

I have defined the following function: randvec[mag_]:= mag Normalize[Table[RandomReal[], {j, 1, 4}]] I would like to format the numbers in the list so that they ...
0
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2answers
73 views

How to generate random vectors without repetition?

Say we have three elements, 0,1,2 and we want to generate 1000 random vectors of length 7 with these elements, i.e. {2,1,0,0,0,0,2} How can we do this without ...
2
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1answer
53 views

List of all possible unions of given sets

I'm trying to generate a list of all possible unions of some sets to generate a topological space from a given basic sets. For ex: Given {1}, {2}, {4}, {1,3} I ...
1
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2answers
96 views

Can one make `Do'-Loops of arbitrary depth?

In the documentation for the Do[...] function, a loop of nesting up to any number of layers is supported. But to apply their function, one needs to know ahead of time how many layers of loops they're ...
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0answers
45 views

Rotate and translate previously-plotted data

I have the following: Show[data1, data2, data3,PlotRange -> {All, All}] where data1, ...
1
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1answer
57 views

Generate part of peak with only initial part of peak

If I have the following data: ...
2
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1answer
58 views

Removing certain numbers from a list

If I have an list of numbers {1, 2, 4, 70, 11, 20, 56, 79}, is there a way to remove the list {2, 4, 56} from that list? In my ...
0
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0answers
54 views

Appending to a list in a For-loop

I am new to Mathematica. Here is my problem: Given the matrix $\qquad M = \begin{pmatrix} 2 & -1 \\ 1 & 2 \end{pmatrix}$, sum the overlap (inner-product) of it's eigenvectors $\qquad \bigg\{\...
0
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1answer
79 views

Improve running speed of FullSimplify function

How can I make this code faster? The checking with FullSimplify takes a lot of time. ...
5
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4answers
139 views

How to drop/extract elements of a list which starts with Plus

I have the following list : list={a^2, b^2, a^-1, a^2+b^2, (a+b+c)^-1, (a+b-c)^-2} Do[Print[list[[i]]//FullForm],{i,1,Length[list]}] I want to break this list into ...
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0answers
34 views

Iterating MovingMap with Nest

I am trying to create a background correction inspired by the PyMca strip background method. The data I'm trying to correct is a HPLC chromatogram in the form of a ...
3
votes
1answer
69 views

Remove errors from sublists after Excel import

I have a very long list such as: https://pastebin.com/9vYDLsVp At the end of each sublist for some reason I have {,-6}. How can I remove that from each sublist of ...
3
votes
1answer
103 views

Build Table of Edge Weight Sums

Is there a convenient way to build a table as generated by the code below where a 5th column (at the far right) could be added to the table that is the sum of the edge weights for the nodes in a given ...
0
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1answer
70 views

List Plot Error [closed]

I've produced this simulation of a superhetrodyne radio receiver. I'm pretty sure it's solid for the most part but I'm getting a list plot error. ListPlot::lpn: {{{1.,0.},{2.,0.00104953},{3.,0....
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0answers
31 views

InterpolatingPolynomial: magnitude of coeffictions

I have a list of the type {{x,y},f} and want to get an InterpolatingPolynomial for that list. The x values all run between 1.3 and 2, the y values between 0 and 1. ...
3
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3answers
106 views

Alternative to Inner which allows level specification

Is it possible to restrict Inner to a certain level? According to the documentation, the expected behaviour for Inner is to ...
4
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2answers
55 views

Smart under-sampling of a large list of data points

I have dielectric functions of materials as lists of value pairs {{x1, y1}, {x2, y2}, ...} and unfortunately some of them are quite long, which is a bother in ...
6
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1answer
78 views

Partitioning a list to several depths

I an aware of the Partition command which partitions a list into sublists. I'm curious as to whether there is an efficient way to partition a list several times ...
4
votes
3answers
223 views

DeleteDuplicates and select which one to delete from a pair

In this case if two lists with the same total then one list is deleted. Can I add one more condition to choose which one to be deleted, for example the deleted list between the two is the one where ...
4
votes
5answers
323 views

Randomly Choose from list but meet conditions

I have a list of integers from 0-99, but some of the integers have been randomly removed. I want to pick a random integer that is still in the list, let’s call it ‘a’ but if a+1, a+2, and a+3 are not ...
8
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3answers
446 views

Improve running speed for DeleteDuplicates

How to make this faster? I want to remove elements that satisfy the condition below but it's way too slow. ...
2
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0answers
38 views

How to extract the same entries from two tables? [closed]

I have 30000 entries in two tables. Now, I want to extract those two entries which are the same. How can I do it? For example, I have two tables, say T1 and T2; ...
2
votes
2answers
193 views

Given a list of linear equations, what is a neat way to use solve on the equations of this list? [closed]

Suppose I have a list of equations, say {2x+b+3c=3, 7x+2b+c=1, x+b+9c=-2} what is a neat way to use Solve[] on that list? ...
3
votes
1answer
53 views

Removing specific entries from a list

I have the list L=8; indx = Range[-π, π, 2 π/L] (* {-π, -((3 π)/4), -(π/2), -(π/4), 0, π/4, π/2, (3 π)/4, π} *) Now I want to delete specific elements of this list,...
1
vote
3answers
58 views

A conditional list generator with stored argument values

I have already made this and the question is really about "how to make this faster and more general (to save the 4 keypresses of D,o,[ and ] that have to be made per-parameter)" The function:...
4
votes
4answers
80 views

Delete the sublist which can be others' subsets

given lst = {{1, 5}, {2, 5}, {6, 8}, {6, 8, 9}} I want to remove all the sublists which is any other's subset. For the above example, remove ...
1
vote
1answer
42 views

Subtracting elements of two sublists [closed]

I have two lists: listA = {{h1, h2, h3}, {h4, h5, h6}, {h7, h8, h9}}; listB = {{g1, g2, g3}, {g4, g5, g6}}; and I need to subtract sublists to construct a list <...
2
votes
1answer
56 views

Flatten for ListDensityPlot [closed]

How do I flatten a list of the form {{{1, 2}, 3}, {{4, 5}, 6}, {{7, 8}, 9},...} to put it in the form ...
9
votes
6answers
248 views

How to sort and extract a list containing products

I've some difficulties with lists containing products as elements, e.g. list = {A B A, A K B, A K R}, where A and B are from the same 'family', let's call it sector ...
0
votes
1answer
37 views

Define a function, that evaluates other function

I want to be able to write a Function (Operator), that gets 2 arguments. The first argument specifies the kind of "operation", the second the function on which to apply the operation. It ...
2
votes
2answers
135 views

Functional realisation of do-loop

I'm currently optimising my code and I'm using a lot of loops, so I was wondering if there is a smarter or faster way to do things like: ...

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