Questions tagged [list-manipulation]
Questions on the manipulation of List objects in Mathematica, and the functions used for these manipulations.
548
questions with no upvoted or accepted answers
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Find algorithm or generator formula with automated procedure and pattern recognition
I am trying to find a generator formula for the discriminant of a polynomial and believe it would be an interesting problem for the Mathematica community to know how to automate evaluation of certain ...
- 483
2
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0
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213
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Problem with ParallelTable?
I am trying to numerically solve Bloch equations using Euler's method. My code is the following
...
- 581
2
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0
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161
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Compilation of a function that needs to call Subsets
I'm working on a code that runs many (easy) operations on combinations (subsets) of different size (6, 7, 8, 9) taken from a big set of numbers (normally more that 40). So, this means the code has to ...
- 2,037
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141
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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 ...
- 171
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133
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An efficient way to merge a pair of 4d arrays of non regular length lists
Question
I have two 4 dimensional non regular length lists of complex values. I have working code however it seems quite slow and I am not sure how I could improve this.
Mathematically I am trying ...
- 153
2
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0
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706
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How could I make an Excel-like table?
I am looking to build a simple Excel type of a table with four columns.
I have spent some time researching Mathematica documentation, but haven't come across a way to implement that.
Here is a picture ...
- 21
2
votes
1
answer
381
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Generating a variable size table one element at a time
I can produce a variable size list of strings like AACBBAABC with this code:
...
- 51
2
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0
answers
91
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The number of real values assumed by combinations of complex roots of a decic
Define complex conjugate as the pair of complex numbers $a+bi,a-bi$. Assume you have 5 such pairs and they are the 10 roots $x_i$ of a 10th-deg equation with integer coefficients. In general, how many ...
- 427
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150
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Need an explanation on how code from journal works
I was reading a paper from Mathematica Journal. It gives code for calculating subsets.
...
- 2,053
2
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0
answers
150
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correct usage of ParallelTable
I am trying to parallelize my script. Here is a MWE of how I have done it:
...
- 1,233
2
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0
answers
675
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Generating a function which outputs possible chemical reactions
I want to make a list of chemical reactions and I write them down in a $\require{mhchem}\LaTeX$ format. They are of the following form
$$NA_n^i+MB_m^j \rightarrow \hat NA_{\hat n}^{\hat i}+\hat MA_{\...
- 1,485
1
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0
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98
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Optimize grouping of list of lists by elements
I have a sorted list of lists of size ~200,000 x 3. The data are such that the first element of each triplet loops through i = 1, 1.1, 1.2, ..., 199.9, 200, and for every value of i, the second ...
- 11
1
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52
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Fitting experimental data to a plot with different x-axis paths
Given Mathematica code of eigenvalues in different variable-paths , I want to add experimental data in the path Gamma-X ; X-Gamma ; and M-Gamma .
Here is the code :
...
- 117
1
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0
answers
53
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SameTest for arrays of points
I need to gather arrays of points by some intuitive SameTest,
so for some tolerance the next arrays will be treated as the same:
Next code looks like suitable for ...
- 1,197
1
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0
answers
63
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How to remove curly brackets from a list of functions?
When I'm creating a plot I standardize the format by predefined parameters, like:
...
1
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0
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43
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Finding and manually weeding out images in ClusteringComponents clusters
I have processed images using the following code, where list1 and list 2 are x and y axes, sample of images:
...
- 113
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0
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164
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How to show the limit of two functions in a code approach zero?
I don't know how to shorten the program, the entire code is required to understand everything:
...
- 39
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0
answers
46
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How to join common dates on a TemporalData set with TimeSeriesThread (possible Bug)
Bug introduced in version 13.2 or earlier
WRI have forwarded the problem to their developers. Case Number 5029803
I am trying to join TemporalData with many paths ...
1
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0
answers
64
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How to Name a Path in TemporalData?
Preamble:
I am working with stock prices and need to perform calculations on them. And then extract the information for further calculations.
TimeSeries/...
1
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0
answers
52
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Selecting elements with a particular slope
I have a dataset for which I want to identify 'groupings' based on three criteria, but only one of them is giving me a headache. The criteria are that each group must:
have a minimum number of points ...
- 1,396
1
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1
answer
44
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ListInterpolation of a geopath list of lat/long without reformating?
I have a list of lat/long pairs and would like to interpolate. Sending the list of lists of lat/long directly to the first form in the documentation as ListInterpolation[{f1,f2,..}] noting "The ...
- 11
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0
answers
50
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Comparing performance of `ParallelMap` with pure function
Test data are here:
q = CloudGet[
"https://www.wolframcloud.com/obj/874e3b18-808a-404a-aaa0-4e3ad1ac4668"];
I construct interpolation and an equi-...
- 3,733
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57
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Report sum of each list seperately
I'm looking to calculate the variance of the total of multiple lists. To do this accurately I will need each list sum to be reported separately, and recorded in a list, to then perform the variance ...
- 163
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0
answers
132
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SortBy the second element in the sublists
Is there a way to sort sublists in a list by the sublists' second element?
For example, if the list is:
...
- 425
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0
answers
133
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Why is my module saying "cannot assign to raw object" when I run it more than once?
I am trying to solve the shortest path problem in Mathematica. My code looks like this so far. I first import the list.
...
1
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1
answer
168
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ListLogPlot for positive and negative values
I am trying to plot the following set of points on Mathematica:
...
- 163
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1
answer
132
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How to separate parameters from a list based on certain conditions?
The following codes create a table of parameters Br and Dr based on corresponding parameters b and c. How to separate/divide the list/table of Br and Dr for which corresponding b or c are negative ...
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49
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how i convert lists' elements x to this lists' elements y and how i get elements from nested list?
i have nested list as follows
x = {{x11, x12, x13}, {x21, x22, x23}, {x31, x32, x33},{x41, x42, x43}} = {{1, 3, 5}, {3, 4, 3}, {2, 6, 7}, {2, 6, 8}}
i want to make ...
- 369
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0
answers
36
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Generating a table of lists following the set of rules
I am trying to generate a table of degree sequences for simple connected graphs for a given number of nodes.
Example output for $n=4$:
...
- 81
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0
answers
63
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An error in the short form of a two-dimensional array?
I noticed very strange behavior in the function Short when applied to a two-dimensional list of real numbers in Mathematica 12.3. Consider that
...
- 101
1
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0
answers
40
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Efficient construction of a formal polynomial using list manipulations
I have a code which is probably extremely inefficient given my inexperience with Mathematica list manipulation. Take as input data:
...
- 1,327
1
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0
answers
33
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Placing plots around a circle with SectorChart
I need to position some graphs around a circle so that each occupies a sector. There're 18 graphs in total and the first five are shown below:
...
- 1,304
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83
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How to DeleteDuplicates from a list of Rules having set to different values whereby we wish to drop the last occurrence?
About This Function
This will eventually set default values for Options based on the end users preferences so that no OptionsPattern need ever be set. The symbol<...
- 2,397
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0
answers
57
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Reading *ptw files into Mathematica
I have a SWIR camera that outputs raw image files in *ptw format. I need to read them into Mathematica for image analysis. I know that such files can be read into Matlab and C++, so there must be a ...
- 11
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0
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104
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How to fix Mathematica crashing in the following case?
I have a problem with Mathematica when trying to glue two tables together.
The tables have the form
...
- 4,642
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71
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Dividing list into smaller list using a set of rules?
Suppose we have the list for $n\in\mathbb{N}$
Range[1,n]
We choose the number in the list where $x=1$, $x=n$ and $x=1+(n-1)/2$ round closest to and the numbers ...
- 39
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85
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1
vote
0
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87
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1
vote
0
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92
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Inconsistency of interpreting TableForm inputs
Bug introduced in 12.3.1 or earlier and persisting through 13.2.0 or later.
Consider this line of code and its result:
...
- 952
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0
answers
91
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Set w/Log steps to generate a Table
I'm trying to generate a Table with data with the form
data=Table[{x1,x2,expr1},{x1,x10,x1f,x1step},{x2,x20,x2f,x2step}]
In the context of my ...
- 625
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87
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Extension of /@ operation
If I want to extend this useful operation /@ into a "matrix" version, say for example
(#1*{Cos[#2], Sin[#2]}) &/@
...
- 379
1
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0
answers
44
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Sortable Grid-like control for large data sets?
I've been using a roll-your-own function for a while that's a wrapper around Grid which adds a couple things I always use, like headers, dynamic sorting, filtering, and clipping (only showing the ...
- 763
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0
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68
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How to create this list
Suppose I have two kinds of operators $a[i,j],a^\dagger[i,j]$ where i is a non-negative integer and $j=\pm 1$, I want to create a list containing all possible products of
$ a^{(\dagger)}[x_1,j_1]a^{(\...
- 51
1
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0
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34
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What subsequences does SequenceReplace consider
Consider SequenceReplace[{a, b, x, x, a, c}, {a, e_} :> e].
What subsequences does SequenceReplace consider?
The ...
- 789
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0
answers
48
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Error using list of discrete variables with WhenEvent
I came across an error when using a list of Discrete Variables with NDSolve and WhenEvent. As you can see in the minimal example, where I defined the 'testevent', when I use ...
- 115
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0
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100
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1
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70
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1
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83
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What is "Flatten" doing to my elements?
Here's some of my code. x1 results in returning the position of a list in a {{{n1}},{{n2}}...}. Im trying to flatten it such that the list reads out as {n1,n2,n3....} some how it's adding elements.
...
- 11
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64
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Problem using KarhunenLoeveDecomposition
I have a matrix called stochasticData.mat which size is 211302*50 and I need to perform the Karhunen-Loève decomposition on it to calculate the uncorrelated random variables. Note that stochasticData....
- 223
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85
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Symbolic add of 32Bit Registers
I would like to perform multiple 32bit word register additions (mod 32 add. with variables of Boolean type shuffled with symbolic type).
For this task I implemented a ripple adder function:
...
