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

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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
197 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
112 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 & ...
2
votes
3answers
111 views

Shorthand to write repetitive test in mathematica

I have the following set of Mathematica statements: ...
1
vote
5answers
400 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
110 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
96 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
31 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
96 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
216 views
3
votes
2answers
91 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
201 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
206 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
72 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
219 views

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

I have a list the form: ...
2
votes
2answers
209 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
335 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
72 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
165 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
150 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
452 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
231 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
37 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
140 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
173 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
88 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
214 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
778 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
65 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
274 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
425 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
71 views

Do TakeWhile and LengthWhile work with Greater? [closed]

TakeWhile[{1, 2, 3, 4, 5}, # > 3 &] gives me {}. Similarly ...
4
votes
4answers
120 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
211 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 ...
0
votes
3answers
75 views
1
vote
3answers
73 views

Delete permutations of subtables in a table [closed]

I've got a table of tables: $A=\{\{a,b\},\{b,a\},...,\{a,b,c,d,e\},\{e,d,c,a,b\},...\}$. How do I do to remove backward duplicates, or more generally permutations of duplicates in the table? For ...
0
votes
1answer
57 views

Create a Table depending of two variables [closed]

I tried to create a table depending of two variables as: W= Table[{G[[i]], G[[j]]}, {i, 1, 3}, {j, 1, 3}] I wanted it to look like ...
6
votes
3answers
120 views

Comparing elements of a set and deleting elements based on a criterion

I have a function that has two inputs. The first input is a set of 2-element sets, and the second input is a single 2-element set. My function complements each 2-element set with the second ...
0
votes
0answers
39 views

Procedure argument value change [duplicate]

I'm trying to create my own hamiltonian cycle algorithm using Mathematica for school, and I'm stuck on a syntax issue. I get the following error: ...
6
votes
5answers
438 views

How to switch from List of rules to Association? [duplicate]

Considering we have a list of rules: ...
12
votes
1answer
192 views

ListConvolve Memory Hemorrhage

Bug introduced in 10.0.0 and fixed in 10.2.0. I wrote a routine that convolves an impulse response array with a test array and checks for the RMS difference between that convolution and a data ...
0
votes
2answers
83 views

Writing a function with variable arguments [duplicate]

I want to write a function which takes multiple arguments varying from 1 to n, where each argument is a triplet. sublistProduct[{$a_1,b_1,c_1$},{$a_2,b_2,c_2$},...] = { $\Pi_{i=1}^{i=n}a_i ...
1
vote
2answers
118 views

How to make function accept list of rules as an argument?

Considering the list of rules: r= {"a" -> "1", "b" -> "2", "c" -> 3, d -> 231, "e" -> 1.25}; I want to have a function ...
2
votes
3answers
145 views

DeleteDuplicates in a list of 2-tuples under condition

Having a list of 2-tuples, I would like to delete such 2-tuples that have 0 at second position, but only those, whose first element is not unique in the list. E.g. ...
1
vote
3answers
207 views

How to manage list of list of rules?

Considering we have a list: str = "{1 -> {a -> aa, b -> bb}, 2 -> {2a -> \"{b -> bb}\"}}" Bringing this to expression gives: ...
4
votes
1answer
86 views

Automatically assign Variablenames to multiple checkboxes

I want to implement the option to import data from Excel and then the ability to trim this data in order to fit the needs. The import from Excel: (source) ...