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

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6
votes
1answer
42 views

Heading in Table Form Question

I have: modadd = Table[Mod[i + j, 3], {i, 0, 2}, {j, 0, 2}]; TableForm[modadd, TableHeadings -> {{0, 1, 2}, {0, 1, 2}}] Which produces: How can I put a ...
3
votes
4answers
176 views

select elements in a list

I am new in Wolfram Math and I need a help in making a simple program. Let's suppose we have a list: list = {{1, 11}, {2, 7}, {4, 2}, {7, 9}, {-2, 3}, {-1, 10}}; ...
0
votes
4answers
50 views

insert elements into 2 D array [duplicate]

say I have a 2 dimensionsal array like a={{1,2,3},{4,5,6},{7,8,9}} and a vector like v={10,11,12} I want the result to be ...
4
votes
1answer
103 views

UpTo for negative indices?

The symbol UpTo emerged as a sort of "safe take" in version 10: Take[{1, 2, 3}, UpTo[4]] (* Out: {1, 2, 3} *) But it wasn't ...
2
votes
2answers
81 views

Group Datasets and take minimum/maximum

Good Morning I have the following dataset: And I try to reach this output: key: only one row per key text: join all texts of the rows with the same key (but no duplicates) min: take the lowest ...
8
votes
2answers
97 views

For loop works at top-level but not in a function

Why does this work: For[i = 1, i <= Dimensions[list][[1]], i++, list = Insert[list, i, {i, 3}]] But this doesn't: ...
4
votes
3answers
125 views

Alternative forms to Table for iterating over replacement rules

I have a multivariate polynomial x. I get coefficients of various monomials using CoefficientRules, which returns a list of ...
9
votes
1answer
192 views

Fast implementation of Metropolis-Hastings update with multiple sets

This is an optimisation question rather than something I am unable to do. I have a naive, primitive working version of the code (I submit it below) but I am trying to make it work faster. I am asking ...
-1
votes
3answers
76 views

Create table of elements which belongs to specific sets

I would like to produce elements (preferably by Table or For-If commands) that they belong to specific sets. For example I want to write positive integers from 1 to 100 such that they are $2 \pmod 3$, ...
3
votes
1answer
226 views

Minimize sum of array elements subject to conditions

I have array where each point at different times are shown parameters ...
3
votes
2answers
79 views

Generating a sequence of lists [closed]

I have learnt how to generate a sequence of numbers, but now I come across a question whether it is possible to generate e sequence of lists. Say, I would like to generate ...
8
votes
3answers
345 views

Give a element rank list of a list

SeedRandom[417] list1 = RandomChoice[Range[22, 28], 4] {22, 24, 26, 23} We can get the rank list ...
1
vote
1answer
51 views

Rearrange the list with some rules

I am trying to solve physic problem on operators which are not commute. However, I am not good at coding, so I am having some problem with Mathematica code. Let's define my list such that ...
0
votes
2answers
63 views

How to prove that an equation can be divided by any n?

I'm new to Mathematica and came across with the problem. I can't prove that (for example) 2*n is always even no matter what n ...
-1
votes
1answer
46 views

How to graph the max and min values of a sheet?

Hi I just start working in Mathematica version 10.3.1 and I want to graph a sheet of data that I created in Excel (yeah i use Windows). The problem is i have so many data; 200 columns and 50 row of ...
-1
votes
1answer
45 views

Generate list of first 100 prime number? [closed]

I know how to generate a list of prime numbers up to a limit, but how would I generate the first 100 prime numbers in a list?
3
votes
2answers
101 views

Using “Outer” with “ChineseRemainder”?

I'm looking to build a $7\times3$ matrix using ChineseRemainder. Trying to use ${0,1,2,3,4,5,6} \pmod 7$ and ${3,15,21} \pmod {30}$ so that the first element of ...
3
votes
2answers
70 views

Calculate Cumulative Mean and Standard Deviation of a list without FOR loops [duplicate]

I have a simple list mylist={x_1,x_2,...,x_N};. Now I want to map a function over this list, e.g. the Mean and StandardDeviation functions, so that it will give me ...
5
votes
3answers
123 views

How to partition a set with a condition on subsets?

I want to partition a set of $n$ elements into $k$ subsets with a condition For example: partitioning this set {1,...,5} into 3 subsets with this condition: if $|i-j|<d$ then $i$ can't be with $j$ ...
0
votes
1answer
54 views

Append[] is not working for empty list [duplicate]

I am trying to create an empty list and add an element but the list is not being populated. My code ...
0
votes
1answer
91 views

How to turn a subroutine into a function?

I've written a subroutine that takes in 6 matrices and after some manipulation returns back 3 new ones. I will use this subroutine fairly often in this notebook so I think it would be easier to turn ...
0
votes
0answers
40 views

Do[If[ *stuff* ]*arguments*]: Increasing range over which Do iterates changes results of If?

Summary: If I run the same Do[] expression but with the variable(s) over which I am iterating taking on more values (but same increment), an If statement inside the Do[] evaluates as false a few times ...
6
votes
2answers
342 views

Performance of calculation of means squared displacement

How can I improve the performance of the following code which calculates the mean squared displacement for coordinates stored in data? Here for each time difference ...
0
votes
1answer
41 views

Help with limiting output

I wrote this program on Mathematica (which I am very new to): ...
11
votes
4answers
484 views

How do I extract a matrix of only positive numbers given a set of assumptions?

I want to divide a matrix: mat = {{a, 0, -b}, {d, a, 0}, {0, 0, -a}} with the following assumptions: ...
10
votes
4answers
268 views

Convert elements of list to string

how easily can I convert elements of this list to string. If I have output like this: {{M, 1, 0, 0, 1, 1, 1, 0}, {A, 0, 0, 0}} And I want something like this: ...
0
votes
1answer
76 views

ListPlot and Show n plots from two lists with large n

For the context, I have been dealing with Random Matrices and Dyson Brownian motion. I have two lists, the first one contains the number of steps, so ...
2
votes
0answers
53 views

Estimating processing time for commands

I am trying to evaluate some equations by using Taylor series of expansion (Series[], ExpandAll[], and Normal[] command), and using n equation and n unknown (Solve). Following is not full command (if ...
4
votes
3answers
130 views

Replicate sublist in new list

If I have a list of lists $a$ and a list of occurrences of each sublist $n$ a={ {1,1,1}, {2,2,2}, {3,3,3} } n={1,3,2} what is the most efficient way to get the ...
5
votes
2answers
320 views

How to construct a dataset with lists as columns

So I know this should be pretty easy, but I cannot seem to find a solution anywhere, so thanks in advance for your help: I have three Lists (with numbers as ...
8
votes
4answers
230 views

How to get this list with a terse method

If I have like {a,b} and I want to get {{a+1,b},{a-1,b},{a,b+1},{a,b-1}} We don't care about the ordering of the ...
6
votes
3answers
172 views

How to prevent substitution in a part of an expression?

Background: I am trying to write a program that can execute scheme in Mathematica. Now I have things like {"+", 3, {"-", 2, {"'", {"*", 1, 3}}}}. The syntax ...
5
votes
5answers
279 views

How can one get all possible sublists of a list? [duplicate]

So if list={1,2,3} then output should be {{},{1},{2},{3},{1,2},{2,3},{1,2,3}} or in different order.
-1
votes
1answer
91 views

Lattice model array for distribution of energy [closed]

Edited for clarity I am trying to make a 2-D array constant, lets say 100x100, and perform a function on that. The array would look like ...
0
votes
2answers
56 views

RSolve - basic question about using rules as functions

I think this is basic question, but I can't find it in Help... (I am begginer :P) I have this expression ...
11
votes
2answers
420 views

How to fill a grid make its total be largest

I have a blank grid whose dimension is 5*5. I want to fill it with some number using 1, 2, 3 and 4. But in every blank space if you fill 2, its neighbor (include four direction, such as left, ...
10
votes
10answers
682 views

Matrix indexed by one number

I'm trying to find a generic way (for arbitrary dimensions) to create a matrix like so a[1] a[2] a[3] a[4] i.e where it is indexed by one number, instead of say ...
3
votes
5answers
155 views

How do I select strings based on the number they end in?

I have a list of alphanumeric strings, str = {"ANH7134UR1", "ANH7134UL4", "ANH7134UR7", "ANH7134UL17", "ANH7134UR18"}; that I want to assign each string to ...
5
votes
1answer
93 views

list of all permuations of sublists of a nested list

I've got a certain class of lists with, say, 4 elements, that are lists themselves. E.g. {{1, 2, 3}, {4}, {5, 6}, {7}}. I'd like to find a way to generate a list ...
1
vote
0answers
23 views

How do I add a finite value to one component of a set of vectors [closed]

I have a set of (x,y) values in some *.csv file, when I open them with Mathematica to plot it some of the plots are shifted so I need to add some finite value to one of the components of every vector. ...
1
vote
0answers
42 views

List within a Do loop , i cant get any values [duplicate]

I am having the following problem. I am trying to get some values from solving an equation and apply them into a list but in the output I get nothing but the symbol of the variable... The code is as ...
5
votes
2answers
213 views

Why SetDelayed won't work

I'm trying to do this: Riffle[list = {a, b, c, d, e, f}, tem = RandomInteger[1, Length@list-1]] {a, 0, b, 0, c, 1, d, 0, e, 0, f} But I think this method is ...
5
votes
4answers
198 views

Creating Nested For Loops for modifying values to append to a List

Basically, the title says it all. I am familiar with python, not so much with mathematica. For the program, I am starting out with three unique lists of values for which I am using a triple nested ...
0
votes
0answers
31 views

Envelope of a given table (or plot)

Is there any way to construct an envelope of a given table (list) or plot? For example, I have plotted (used ListPlot of txt-file) And then I want to plot the envelope (upper or lower) of this plot ...
2
votes
0answers
26 views

Find same list elements of two lists [closed]

Example: I have two 2D lists (each list has no duplicate elements): l1 = {{1, 1}, {2, 2}, {3, 3}, {4, 4}}; l2 = {{1, 1}, {3, 3}, {5, 5}}; How can I create a new ...
0
votes
1answer
83 views

How to ListContourPlot a functional eigenvalue spectrum?

We have a (Hermitian) matrix of some finite dimension (n) whose elements are functions of real variables x and y. We wish to plot contours of the spectrum (level sets of the n real eigenvalues) at ...
6
votes
1answer
75 views

Function that counts number of consecutive elements after iterator in Table command

I have a 1D Table, something like this, that I want to turn into musical notes: ...
7
votes
3answers
159 views

Nonzero element positions of a matrix

Let m={{1, 2, 0}, {4, 0, 9}}; I want to find the position of every nonzero element of the above matrix. The code ...
11
votes
2answers
271 views

How to mesh a region using adaptive cubic elements

Assume a list of {x,y,z} coordinates. The coordinates are arranged in a regular fashion through a fixed raster size (called ...