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
53 views

deleteduplicates Delete elements of a list [duplicate]

I have a math problem about Mathematica, I am looking help from you. I hope that you could help me. The Math Problem: list= { {0,0,1},{1,0,0},{0,1,0} ,{1,2,3}}; ...
2
votes
2answers
45 views

How to further process a 2 dimensional list created with tuples

I created with Tuples[{{USD, EUR, JPY}, {UP, DOWN}}] the following result: ...
2
votes
3answers
147 views

How to display the indices/element positions of a ragged array?

I have a three-level ragged array like so: ...
2
votes
2answers
77 views

Adding a tree to a list of trees within a loop [duplicate]

I'm trying to write a function which for a list of trees checks if a given tree is isomorphic with any of the listed, and if not - adds it to the list. I tried to use both ...
1
vote
1answer
110 views

ListPlot[] code for CSV file not working

I have a CSV file with $9$ columns. I want to plot them in the following way. Column $1$ will be along the $X$-axis. Any point $(x_i, y_i)$ of $i$-th curve in the plot will have the $x$ value from the ...
3
votes
2answers
246 views

All possible pairs of two items

I have 4 different items {1, 2, 3, 4}. I want to obtain all possible pairs of two of the items. I have written: ...
4
votes
1answer
497 views

Why is there a huge performance gap using Map with more than 100 List entries

im using Map on a List like this: cube= {{1, 1, 1}, {1, 1, 2}, {1, 1, 3}, {1, 1, 4}, ... , {5, 5, 4}, {5, 5, 5}} Mapping the whole List with 125 entries takes ...
1
vote
1answer
68 views

Replace distinct values of list with values of another list

First of all I´m new to Mathematica; I´m trying to exchange distinct values of a list with values of another list (piecewise). I thought ReplacePart in combination ...
2
votes
2answers
57 views

How do I delete items at the same position from every sub-list within a list? [duplicate]

We have data in a list called megadata where megadata[[1]] for instance are the temperatures of each data point, ...
1
vote
1answer
91 views

Using Map in a function definition

I want to calculate the hessian of a matrix. So each element gets replaced by a 2 by 2 matrix. ...
3
votes
3answers
138 views

Elegant way for map a function over the columns of an array

I have an array data = {{1, 2, 3}, {4, 5, 6}, {7, 8, 9}}; And I want map Standardize over the column of the array. I use ...
4
votes
2answers
135 views

Get part of lousy data

I want to get part of large data. some part of this data is as follows: ...
5
votes
3answers
267 views

Command to insert item into list

Is there a command to insert an item into a list such that they form pairs? In other words to take InsertObject[{a,b,c},d] which will output ...
1
vote
1answer
105 views

DeleteCases that match partially [closed]

Say I have a list of strings L , L2= "some_text-to-delete" and I want to delete all the Li that match with "text" or "delete" DeleteCase only gives the ones that match exactly...
0
votes
4answers
135 views

Using levels in MapIndexed

I am trying to use MapIndexed to manipulate a matrix of data but I am having trouble getting the levels parameter to work the way I would like. Suppose that my data ...
2
votes
3answers
101 views

Table to text string [closed]

I know this is a simple question and there is a single command to do this but I have been looking for the command for 30+ minutes and cannot find it. I have a list that I want to put tabs between ...
6
votes
4answers
463 views

Swap elements in list without copy [duplicate]

I have a lists with 100,000 elements and would like two swap to entries without dublicating the list Example: ...
2
votes
3answers
201 views

Backsubstituting solution into FindRoot and Plot

I want to find roots from a transcendental equation using FindRoot as a function of a real parameter and then plot the solutions vs. the parameter. The following commands work perfectly: ...
3
votes
2answers
94 views

Matrix of given size with unspecified elements

I want to generate a Matrix of given size whose elements are not specified I can use Array[a, {3, 2}] to get ...
1
vote
1answer
114 views

Inverting matrix of unknown size

I have a matrix that has a variable number of columns and rows (but it is always square). The matrix is: $$ \Gamma = \begin{bmatrix} \Theta & 0 & 0 & 0 & T & 0 & R_j \\ ...
0
votes
3answers
84 views

Positions of a string in a list [closed]

Sorry for the bad title..Didn't know how to describe this, feel free to change it to be more specific. I have a list in this form: ...
8
votes
8answers
709 views

Replace interior of matrix with zeros

I have f.e. the following square matrix: ...
0
votes
1answer
40 views
0
votes
1answer
43 views

Sort a multidimensional list row-wise [closed]

Suppose I have a multidimensional list as shown below: RandomInteger[{1,10},{3,7}] I obtain the results: $$ \left( \begin{array}{ccccccc} 3 & 8 ...
7
votes
4answers
585 views

How to find all data points within closed curve

I want to find all data points inside curve as given below: ...
1
vote
1answer
58 views

How to apply function on list of lists with different sizes [closed]

I am not good with slot management when it comes to 2D lists. What is the correct way to map a function on list of lists of different length, where the function needs to act of each entry in each ...
6
votes
7answers
335 views

A problem involving classification of data

Toady, I encountered a problem while trying to classify certain data. I have the coordinates of six points. ...
0
votes
1answer
46 views

Combining list x-y data with a list of errobars into one list (mathematica-style)

Suppose I have a list of data I can ListPlot: { {x1,y1}, ... } , and a list of y-errorbars: {erry1, erry2, ... } Is there ...
2
votes
2answers
183 views

Alternative for MapThread in listable functions

How can I rewrite this more efficiently taking advantage of flo, dem, and Nsup being ...
1
vote
1answer
99 views

references in a nested matrix

I have a nested matrix n: ...
7
votes
4answers
232 views

Position of Subsets in a List

I have a particular list of integers and a matrix whose entries are lists. Say I know that my particular list is a subset of at least some of the elements in the matrix. I want to find an efficient ...
1
vote
0answers
104 views

How to sequentially select, from a large set of tuples (of matrices), those with a certain property

I'm interested in finding a computationally efficient way for selecting all tuples of matrices which have a certain property. The property I'm interested in is that I want the column sum, of f[the ...
0
votes
1answer
48 views

How to cut elements from set of data based on function restrictions? [duplicate]

For example, say I have a set of data which takes the form list = {{1,2,4,5,3,2},{2,3,4,2,1,6},{2,3,4,5,4,3}} where all of the elements have a length of 6. ...
1
vote
3answers
145 views

Binning events with weights

I have two vectors, one containing sampled energies and the other one for each of these energies a weight: e(i) and w(i). I ...
2
votes
2answers
192 views

Delete pairs from a list

I have a data set in which I need to remove all matched pairs of entries - not just the first entry that is duplicated but both entries. To add to the complexity, the pairs must be between different ...
5
votes
1answer
225 views

More efficient Omnibus number determination?

Amusing myself with concepts from "Omnibus Sequences, Coupon Collection, and Missing Word Counts", in particular the sequences. To paraphrase the concept, a string is k-Omni over some alphabet a if ...
5
votes
2answers
101 views

Comparison Operation for Nested Matrices

I have a nested matrix n as bellow ...
0
votes
4answers
83 views

Drop row if sum of part of row is equal to zero

My problem is the following: Suppose I have a matrix A which looks the following: ...
5
votes
3answers
277 views

How do I save/export a list so that it can later be easily imported as a list again?

I have a couple of big lists (each of them contains elements that are themselves lists of two elements, i.e. an element of each list that I have is of the form {x, y}) that I want to save/export. ...
4
votes
6answers
432 views

Insert all elements from one matrix into another

I have two matrices $A$ and $B$ which are the same size. Each element of $A$ is a list of numbers. Each element of $B$ is just a number. How do I insert each element of $B$ into the corresponding list ...
0
votes
1answer
71 views

Assign values to variable names in lists

I hope somebody can help me in this (I guess) simple question: I have a list of variable names ls={w0,w1,w2} and another list of values ...
0
votes
2answers
88 views

How do I sum up p items in a sequence?

I have the following sequence list = {p1, p2, p3, p4 ....} I am summing up the p items as follows: p1 + p2 + 2*sqrt (p21*p2) = p12 p12 + p3 + 2*sqrt (p12*p3) = p123 p123 + p4 + 2*sqrt (p123*p4) = ...
0
votes
1answer
81 views

Matrix operations performed with column-vectors

We have 3 matrices: m1, m2 and b. We want to apply matrix operations (dot or sum) in a ...
4
votes
2answers
241 views

How can I create a class of matrices programmatically?

I am trying to figure out how to create a function that can create the matrix pattern below, where: f[1] returns {{1}} ...
0
votes
2answers
100 views

Defining a function as a sum of several Gaussians

I have a function that is a summation of several Gaussians. Working with a 1D Gaussian here, there are 3 variables for each Gaussian: A, ...
2
votes
1answer
186 views

Deleting selected rows from data table [closed]

I'm an intermediate Mathematica user and the select function presented on Data Table Manipulation in Mathematica: Step 2 was very useful in helping me manipulate a 36Mb data file - 13 columns and 180k ...
1
vote
1answer
54 views

Elements of a List according position in axis

({{a, b}, {c, d}}) a, b, c and d are Lists of 300 length. Their first 4 elements must specify their position in the column (1 column, 2 column, etc) and the ...
2
votes
2answers
91 views

Select words from different rows of column headings

I have a 2-dim array. The first 3 rows have column headings. The heading can be a single word, or 2 words (which take 2 rows) or 3 words (which take 3 rows). For each column I know which row has ...
1
vote
1answer
86 views

Nest Replace Function with different rules

I have a table of data that I want to filter. Any value of zero in the table means that value was not calculated, so it should get populated with the tag "NC". Next the table is filtered for all ...