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

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1
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0answers
92 views

Tracking solutions over a Brillouin zone

Thanks to @bbgodfrey I have a function that finds the two solutions to a set of equations bounded by a hexagonal region (corresponding to the Brillouin zone). It takes the angle ...
2
votes
4answers
139 views

Pairs of data to Classify[]

Suppose I had the following data a={1,2,3,4,5} How would I turn this into b={{1,2,3}->4,{2,3,4}->5} That is, ...
7
votes
7answers
455 views

Generate a list

Given the list o = {xmin, xmax, ymin, ymax}; how can I generate the following list? ...
0
votes
1answer
437 views

How can I use nonlinear model fit with multiple variables? [closed]

I have a data set with four entries. the first three entries correspond to variables in the fit x,y, & z. The fourth entry corresponds to the function value. I am trying to fit this data to a rate ...
0
votes
4answers
177 views

How to trim the zeros from the right of a list? [duplicate]

I need to remove the zeros from the right of an integer list up to the first non-zero element. Such as {0,1,0,0,2,0,0}->{0,1,0,0,2}. Padding zeros can be simply ...
0
votes
1answer
145 views

How to import data from a .mat or a .txt file and manipulate dimensions

I'm new to Mathematica (I know very, very little - so I apologize if anything I say is absolutely wrong) - but I'm trying to upload a file from matlab and arrange it in matrix form. I have a .mat file,...
1
vote
1answer
45 views

Truncating a List of Subsets of Ordered Pairs

I have a set of pairs: ...
1
vote
4answers
164 views

Manipulating List?

I have a huge list with 1000 elements. Manually entering and calculating SUM of probabilities it would take a few hours. Example: list = {1, 2, 3, 3, 4, 3} ...
0
votes
0answers
72 views

Matrix iteration failing after second step

I am calculating 11x6 matrix using different logics as in below code. Problem is in Do loop in below code where I have two different criteria to update matrix "fd". I am expecting logic in IF which ...
0
votes
1answer
63 views

Replace element of matrix based on rule which invloves other element of same matrix

I am trying to replace 1s row of matrix d iteratively from right by multiplying last element in 1st row with (1-int*dt) to generate 2nd last element. The replacement continues till I reach the 1st ...
1
vote
1answer
123 views

How can I reshape my solutions to make a 3D plot?

I need some help on the following. I need to run Solve for multiple values of a and b. To do so instead of using Do, I use ...
2
votes
1answer
70 views

Replace parts of nested lists

I have list of stock data as follows: lis1= {{{1992/10/12, 126.946, AEX}, {1992/10/13, 127.85, AEX}}, {{1992/10/12, 88.487, AFLI},{1992/10/13, 91.825, AFLI}}} ...
6
votes
3answers
238 views

List and patterns

Given some tuple $\{N,M,L\}$ such that $N\geq M\geq L\geq 0$ and $N>0$, how can I generate all tuples $\{n,m,l\}$ such that $n\geq m\geq l\geq 0$ and such that ...
1
vote
2answers
51 views

Gather elements in sublist by first element for the purpose of summing [duplicate]

I have data which looks like this: ...
1
vote
3answers
228 views

2D Interpolation of data file

I hae a datafile with 5 columns of the structure: x_i f(x_i,y_1) f(x_i,y_2) f(x_i,y_3) f(x_i,y_3) f(x_i,y_4) with i = 1 to about 100. Thus there are about ...
4
votes
1answer
114 views

Better method to swap the values of two 2-D arrays

I have two 2-D matrices $A$ and $B$(owns same dimentions) which have the style written as below: $ \begin{bmatrix} a_{11} & a_{12} & \cdots & a_{1k} &\cdots &\cdots & a_{1,2k+...
2
votes
3answers
111 views

Shorthand to write repetitive test in mathematica

I have the following set of Mathematica statements: ...
1
vote
5answers
414 views

Finding roots of transcendental equation and collecting into a list

I am working on a physics reserach project for school and I have run into some troubles working Mathematica. I am a fairly inexperienced mathematica user so any help would very much be appreciated. I ...
2
votes
3answers
116 views

Flattening of Matrix rows [duplicate]

It's got to be easy, but I can't come up with a general solution. m = {{16, 2, 3, 13}, {{5, 11, 10, 8}, {9, 7, 6, 12}}, {4, 14, 15, 1}}; What I'm trying to ...
0
votes
1answer
100 views

How to switch keys in a Map to Association [closed]

I have an association that has parameters for a function. These parameters represent two cases that need to be applied to the function. Some parameter values are common to both cases but some are ...
0
votes
0answers
33 views

How to generate the list of consecutive pairs from a list? [duplicate]

What is the morally right solution to mapping a list {a,b,c,...} to the list of pairs {{a,b},{b,c},{c,..},..}? The solution I came up with feels a little clumsy: Shift a copied list by one and form ...
-1
votes
1answer
98 views

Manipulate excel file and plot

I have a number of .csv files that have the following format: I want to do the following: ignore the last two rows sort all the remaining rows w.r.t the 2nd ...
4
votes
2answers
221 views
3
votes
2answers
93 views

How to re-arrange lists, divide one list into 2 lists with a particular step [duplicate]

How to re-arrange following list: {a1,b1,a2,b2,a3,b3,a4,b4} or this {a1,b1},{a2,b2},{a3,b3},{a4,b4} to get: ...
12
votes
2answers
202 views

Faster trimming of leading/trailing zeroes in rectangular array

Given a (large) rectangular array, e.g. (small for example case): ...
1
vote
1answer
52 views

Collecting specific Lists of data in coordinate form

Note: This might be trivial for many of the users but i am new to mathematica so i don't know!!! Question: Suppose i have three list of data as follows: ...
12
votes
2answers
210 views

why MeanFilter is nearly 100 times slower than MovingAverage for 1D array?

I used to average over my data with MeanFilter before I learn about MovingAverage and thought that these two functions are similar except that MeanFilter is more powerful for its ability to deal with ...
15
votes
6answers
1k views

Finding the period of an array of integers

A simple array of integers is given. The problem is to detect if a pattern is repeatedly occurring in the array, and find the length of that pattern. For example, for ...
1
vote
2answers
75 views

Perform operation on part of a table / create a reference

There is a function f that I would like to operate on a rectangular part of a table t. The part is specified by function ...
1
vote
4answers
226 views

How to check if all the members of list lies in specific range

I have a list the form: ...
2
votes
2answers
212 views

Are there any good mass row/column swapping functions for matrices?

I have the following matrix Keeping the 20 row and 20 column fixed (so the 21st rows and columns because I started at 0)...how do I push each row and column back one spot? I need to push the 0th row ...
5
votes
6answers
354 views

Indexed Map Thread

I'm attempting to MapThread a function of two lists that requires the index of the list values. For example, MapThread[#1*i+#2*j&,{{a,b,c},{e,f,g}}] Where #1 ...
2
votes
1answer
78 views

Simplify on a structured array

Why doesn't Simplify and FullSimplify operate on object generated using SymmetrizedArray? ...
1
vote
3answers
149 views

How to do a Check for every element in the list?

I know how to do a Check for the list in general: ...
1
vote
5answers
166 views

How to split list to strings?

Considering a list: lst = {"1", "2", "3", "4", "5", "6"} How can I have two strings : str1 = "1, 2, 3" str2 = "4, 5, 6" ...
0
votes
1answer
168 views

Add elements of one list to sublists of another list [duplicate]

I have the following list of sublists with different lengths {{1,1,1},{2,2},{3,3,3,3}} and a second list {4,5,6}with the same ...
25
votes
3answers
456 views

Bug in MovingMap (breaking change between version 10.1 and 10.0.2)?

The MovingMap window spec has been changed between version 10.1 and 10.0.2. Version 10.0.2 ...
5
votes
2answers
237 views

Create a list of rules built from data set fields

I want to convert a dataset to a list of features and a list of target values, for use in Predict and also more generally. I know ...
0
votes
1answer
38 views

Strange behaviour of Append [closed]

I have the following situation and I completely do not understand why the second system can be solved but the first (of the same equations, as it seems) cannot. How is it possible? ...
0
votes
4answers
142 views

Make a program that does union of two lists

I have to make a program that gives as a result the union of two lists using a For loop. I can't figure out how to inspect if the elements of a list are different. ...
1
vote
2answers
176 views

Complex numbers from two arrays with Real and Imaginary parts

I have two arrays, containing the real and imaginary parts of a list of complex numbers. Re = {{Re_number1},{Re_number2},...} Im = {Im_number1},{Im_number2},...} ...
2
votes
1answer
97 views

sparse array with list [closed]

i'm trying to populate a sparse array with lists in certain positions, i tried the following code, ...
4
votes
3answers
221 views

How to map over inner keys of nested Associations?

Considering an association: <|"a" -> <|aa-> "asc", bb-> "asd", cc-> 0, ImageType -> "asd", dd-> "asd"|>|> How can I make the inner ...
4
votes
4answers
789 views

Writing a circular matrix

I have two square matrices, $A$ and $B$, of the same size, say, of $m \times m$. What I want is to write a programme/function of three variables, $A$, $B$ and $n$, that outputs the $mn \times mn$ ...
1
vote
2answers
66 views

How can I manipulate this list?

I performed a loop with Table where I solve a system of 4 equations that depends on two parameters: eta and p. I create two lists for each parameter as follows: <...
2
votes
4answers
290 views

How to switch from array to string?

Considering we have an array: a = {2/3, 4/5, 9/7, 3/7, 1/7, 1/9}; How can I get this to be: "2/3 4/5 9/7 3/7 1/7 1/9" ...
11
votes
5answers
427 views

Most efficient way of making pair list from a list

I have a bunch of datasets which looks like: 3 7 1 6 5 8 2 4 1 2 8 1 5 2 5 ... and I need to make a list of pairs such that the first element makes a pair with ...
0
votes
1answer
72 views

Do TakeWhile and LengthWhile work with Greater? [closed]

TakeWhile[{1, 2, 3, 4, 5}, # > 3 &] gives me {}. Similarly ...
4
votes
4answers
123 views

Creating a new list from other two lists using for loops

I have two lists 'ups' and 'downs' where they are composed of positions of an element in a matrix and their weight. For example, ...
4
votes
3answers
212 views

How to highlight the elements in a list that match a pattern?

For example, {{1,2,3},{1,2,3,1,2,3,4,5}}with pattern {1,_,3}is transformed to ...