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

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2
votes
1answer
56 views

Matching and counting reversed pairs in a list

Given a list of character pairs like {{"w", "u"}, {"a", "j"}, {"c", "s"}, {"s", "l"}, ....}, I would like to group the reversed set pairs and then get a total count ...
0
votes
1answer
66 views
0
votes
0answers
26 views

Finding a specific position within a TimeSeries Forecast [duplicate]

Say I have a timeseriesforecast on a series of data, result in $10, 30, 50, 100, 400, 700, \ldots$ I want the programme to output the serial number (position in the forecast-series) of the first ...
10
votes
4answers
327 views

Efficient way to make subsets of list with placeholders

I have an arbitrary list of unique elements: lst = {a, b, c, d} Documentation allows finding subsets with same number of elements, say ...
0
votes
1answer
36 views

Manipulation of ListPlot of an imported list versus first elements

I have seen 1& 2 but I could not find an answer helping me. I have created (by another program) a list as below: ...
15
votes
7answers
1k views

How do I delete all items that occur more than once?

DeleteDuplicates works fine but leaves a single copy of the duplicated item. I need to remove all items that occur more than once i.e. {{1,2},{1,2},{3,4}} -> ...
1
vote
1answer
69 views

making Max and Min work columnwise like Median

I have some data and the rows are grouped according to astGroupsPos (the astGroupsPos are just rows from ...
3
votes
1answer
53 views

A question about the `ArrayResample`

I have a confusion with the function of ArrayResample.This is a illustrative picture in Details and Options about the method of "Bin": Then I make a example like this: ...
0
votes
2answers
54 views

Assigning columns of data from a file to variables extracted from headers

I'm very new to Mathematica. I want import a file in which the first colum is a function f1, the second another function f2. So the file looks like this: ...
0
votes
0answers
63 views

Select positive elements from a list of solutions

I'm solving two equations with two unknowns ...
0
votes
2answers
90 views

Combining two lists by merging element-wise [closed]

I have two lists, L1 and L2, each with some data and two scenarios: ...
2
votes
0answers
38 views

Generating a List of Numbers with “Table” Causing Deviation [closed]

I'm trying to generating a list of numbers with the function table. But it caused a little deviation which I didn't expect. Let's say I need a function like: ...
3
votes
2answers
87 views

Role of Accuracy in numerical evaluations, SplitBy vs GatherBy

This is a follow-up question to this question. I generated a list by substituting the results of a solve[] routine and set: ...
1
vote
2answers
91 views

plotting all solutions of differential equations for many parameters

I have a list whose elements is in the form {{f[x]-> some function of x}}. How do I manipulate it to bring in the form ...
9
votes
3answers
309 views

GatherBy/SplitBy and Sort a list

So let's say I want to group a list of points based on their distance from the origin. I would do something like: ...
1
vote
1answer
72 views

Plotting a two lists generated after running a for loop [closed]

So i had to model and solve a harmonic oscillator, being driven by a random driving force. I have managed to finish that and my program is: ...
3
votes
2answers
50 views

Function for generically controlling 'Manipulate' parameters

I want to use a generic function to generate controls in manipulate, which looks like this: ...
3
votes
1answer
67 views

Reading an exported List

I have exported a list of 2d coordinates as a List: Export["F:\\coordinates.dat", coordinates, "List"]; You can access the ...
3
votes
2answers
84 views

Plot markers for monthly data

I have the following data ...
4
votes
1answer
81 views

Creating a list of unevaluated pure functions with Apply

Suppose I have a list list with length L and a function ...
5
votes
1answer
99 views

Table with List iterator return unpacked list

Table support list as iterator, for example list1=Table[w, {w, Range[1., 10., 0.01]}]; We can confirm that list1 is packed ...
16
votes
3answers
430 views

How to group and join points

It seems there are many similar questions on Mathematica.SE, but none addresses (to the best of google) exactly my problem. I have the following data: ...
1
vote
3answers
126 views

Compute intermediate totals using Select and Plus in a list

I have to total per year of weekly results of a function which are in a table with 3 rows: one with the result of the function, one with the week number and one with the year number. I am almost sure ...
4
votes
1answer
83 views

Is it possible to recover the efficiency of ListConvolve when generalizing the convolution?

I've noticed that, while ListConvolve is very fast, it becomes much slower when you use anything but the standard Times,Plus as ...
2
votes
0answers
52 views

How can I convert some data in TableForm to a list form like as {{0,1}, {1,2},{…,…},…,{m,n}}? [closed]

How can I convert some data in TableForm to a list form like as So, I have some data there I take from laboratory, but the data has a TableForm 0.0 0.2174 1e-06 0.2178 2e-06 0.2172 3e-06 ...
12
votes
7answers
628 views

Brackets around each item in matrix

I have a matrix where every item in the matrix has its own brackets that I do not want. How can I remove the brackets around each item?
0
votes
1answer
48 views

How to make an empty list inside a module program? It consatly spews errors [duplicate]

Okay, so, I'm trying to write a program within the module. It goes like this: create empty list, join it with a sample from a certain set called MyList, and then repeat it certain number of times. ...
19
votes
5answers
485 views

Partitioning a list when the cumulative sum exceeds 1

I have a long list of say 1 million Uniform(0,1) random numbers, such as: dat = {0.71, 0.685, 0.16, 0.82, 0.73, 0.44, 0.89, 0.02, 0.47, 0.65} I want to ...
1
vote
1answer
59 views

How to refer a number in a list with two columns, first one is a number and the second one is empty? [closed]

Let's say, I have defined a list as list = {{-31, -31}, {52, }, {34, -11}, {-38, }, {78, -44}, {-36,14}, {-9, 98}, {33, 6}, {82, 99}, {-85, -10}} As you can see, ...
7
votes
1answer
124 views

Add terms to nested list

Suppose I have a nested list of the following: list={{1,2},{5,8},{4,1}...} I would like to add a number to each first term of the list. The output would be ...
2
votes
1answer
100 views

Automatic text-wrapping in labels in `TimelinePlot`

Part-related to this question and part-related to this one, I would like to make use of the new features of TimelinePlot in 10.3, but would like to incorporate some ...
3
votes
1answer
77 views

Calculating products of given length of two matrices

I have the following problem to solve. Let us have two given square matrices $A$ and $B$ of the same size and a positive integer $n$. I would like to produce all products of length at most $n$ of ...
3
votes
1answer
130 views

Efficiently generating tuples with Outer

I'm trying to efficiently generate tuples of lists of objects that satisfy a given criterion. The similar questions that I have found on this website end up finding a specific workaround for the given ...
1
vote
1answer
36 views

Reverse element in nested list [closed]

Suppose I have a list as the following: list={{1,9},{7,0},{8,6}....} How can I reverse the element in such way that the output would be the following: ...
3
votes
0answers
56 views

Weird behaviour for a vector InterpolatingFunction inside an NDSolve

I have run into some weird behaviour on the part of NDSolve which I find pretty bizarre and which I would like to understand better. Suppose, for the sake of ...
2
votes
0answers
49 views

Transposing a table [closed]

I created this table so that it is a collection of 5 different functions that I need. It outputs the values that I want, however, I cannot figure out how to get the orientation right. I would like to ...
1
vote
2answers
68 views

Create an indexed list of functions [duplicate]

I am trying to use a Table to create the following object: {f[#,1]&,f[#,2],f[#,3]} The obvious doesn't work, ...
1
vote
1answer
39 views

How to create sublists of consecutive elements? [duplicate]

I have a list of elements, for example: myList={5, 12, 16, 18, 19, 24, 28, 29, 31, 32, 35, 42, 43, 47, 50, 53, 60, 61, 62, 64, 79, 82, 84, 92, 105, 128, 136, 153, 154, 155, 156, 158, 159, 160, 164} ...
0
votes
1answer
48 views

How to apply a user-defined function to a list [closed]

I'm using Wolfram | Alpha Pro; I have a function f[n] = 351n^(-0.7); How do I apply it to each element of a list like {2, 9, 22}? f/@{2, 9, 22} just results in ...
2
votes
1answer
106 views
5
votes
2answers
258 views

Max of imported numerical data will not work

I loaded a list with 400,000 values from a file. The list was loaded correctly as I can get it's length (by Length[]) and I can also plot it. Why can't I get the Max or Min of this list though? When ...
1
vote
0answers
21 views

Append in For loop doesn't work [duplicate]

I want to simulate a projectile motion under the effect of air resistance by using Append in a For loop, but there appeared to be no changes in the two lists I defined for storing horizontal and ...
4
votes
1answer
146 views

How do I disable that Mathematica orders terms in lexicographic order?

I have matrices with entries where the order of the entries is important. Unfortunately Mathematica resorts terms in products in a lexicographic order. For example, ...
2
votes
1answer
34 views

Encoding/Decoding matrices as integers, integers as matrices [closed]

I want to convert large binary matrices of m x n dimensions into integers, and then to convert these integers to the original matrices. I attempted the following: ...
0
votes
0answers
29 views

DeleteDuplicate from a list with {x == y, y == x} -> {x == y}; [duplicate]

How can I tell Mathematica that it should delete equal elements from a list, which aren't in the same order. For example list={x == y, y == x} ; should become ...
4
votes
0answers
62 views

Create an adequate 'training set' to train a ClassifierFunction which performs the role of the built-in `SubsetQ`

I am trying to "grow" my own SubsetQ function using Machine Learning methods. My cSubsetQ when given two lists (listA and ...
15
votes
3answers
477 views

Generating Tuples with restrictions

I am interested in a certain subset of all tuples. Generating all with Tuples and then filtering is wasteful, and will "blow up" very quickly. For a concrete ...
1
vote
1answer
64 views

Monitoring a matrix with changeable elements as Manipulate in plotting [closed]

If we remember, Mathematica has an ability to show a Psudo-window of plots for monitoring the effects of some changeable parameters in the functions. For example ...
2
votes
4answers
64 views

Partition list into sublists of decreasing length [duplicate]

For example, I would like to partition {1,2,3,4,5} into {1} {1,2} {1,2,3} {1,2,3,4} {1,2,3,4,5} with just one line of code. ...
2
votes
2answers
107 views

plotting eigenvalues with devoted level coloring

I am about to plot eigenvalues of a matrix versus varyingj's. ...