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

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0
votes
2answers
70 views

Uniting lists of lists

Here's what I'm trying to do. First a simple example: ...
1
vote
1answer
70 views

Apply function to a part of a list

Let's say I have some data: data={{a1,b1},{a2,b2},{a3,b3},{a4,b4},...} and I would like to apply the function: f1[x_]=x*5 to ...
4
votes
2answers
86 views

Threading sublists on list

Suppose I have a list of the form: list = {a, b, {c, d}, f, {g, h}} i.e. an element of the list could be another list. I want to 'thread' each element of the ...
0
votes
1answer
38 views

Manipulation of imported Datafile

Since I am solving a differential equation in a for loop with NDSolve ...
2
votes
2answers
35 views
3
votes
1answer
116 views

Plotting a table with many y values

I'm trying to plot a bifurcation map for a Lorenz System. I have a function (called estables in the code that follows) which, for a certain value r, returns the ...
0
votes
0answers
44 views

How to apply a function to a list, being able to use a list index inside of the function? [on hold]

In the documentaion I find things like: M = {a, b, c}; kappa[x_, y_, z_] := x PauliMatrix[1] + y PauliMatrix[2] + z PauliMatrix[3] kappa @@ M // MatrixForm But ...
1
vote
1answer
179 views

Finding Coordinates of a Peak on a Plot

I have plotted a graph from a CSV file which consists of two columns of data Time and Intensity. I simply want to find the time where the intensity is largest. This code: ...
6
votes
1answer
102 views

Filters on image vs data

I was using GaussianFilter and realized that applying it to an array yields a different result from applying it to an image. For instance: ...
-1
votes
0answers
30 views

Insert several sequential alphanumeric characters pdf [on hold]

As I can make it through "this" directory 1 to "this" in the directory 2 and so on for 50 pdf, Deputy sample directory Example
3
votes
3answers
166 views

Looking for a better way to delete an arbitrary list of rows from a matrix

Delete is not suitable to delete the rows of a matrix, as illustrated below: ...
1
vote
3answers
121 views

Basic Programming in Mathematica - How to build a loop [on hold]

I want to build a loop with the following rules: I have a list a={5,7,8,9,5,6,8,6,7,8}. I want to print the mean of the first two ...
16
votes
4answers
479 views

How to enumerate all possible binary associations?

Suppose I have a list of symbols like: {a,b,c,d} I would like to enumerate all possible binary associations (combining symbols and/or sublists pairwise): ...
0
votes
0answers
30 views

Find the variables in a set of linear equations [closed]

Suppose I have a set of linear polynomials with integer coefficients, how could I extract the list of variables? Say given the following ...
12
votes
3answers
209 views

Exclude overlapping lists while keeping disjoint- and sub-lists?

Consider a function f[l1_List,l2_List] which is given lists of integers. Whenever two of the lists contain completely disjoint sets of integers OR one of the lists ...
4
votes
2answers
126 views

Select non-zero elements [duplicate]

I have a function that generates a list of numbers and variables . e.g. F[w]= {wx, wy, 5, 0} I want to select all non-zero elements i.e. ...
2
votes
1answer
9k views

Table - find index of the maximum element [duplicate]

Let's suppose that I have table t = {1.23, 3.4, 10, 34, 1.78, 0.98, 12.56}. To take the biggest element I can use Max[t] ...
2
votes
3answers
143 views

What is an efficient way to pick out consecutive, same first-letter words from a list?

Taking a list of words, I'd like to pick out consecutive words that start with the same letter. The output should be a list of these pairs. The following is relatively slow: ...
0
votes
1answer
48 views

How to get a speicifc element from unknown number of lists?

I have a mathematica function that returns a list of the form: ...
0
votes
2answers
76 views

Fitting a Gaussian model to specific section of my list?

I'm analysing some Decay sepctrums for a Nuclear Physics project. I need to fit a gaussian model to a specific X-Ray peak to determine the centroid so I can get a good channel-energy calibration. ...
0
votes
0answers
34 views

Append value to list automatically when day changes

I am trying to append values to a list automatically when the day changes, is there a way to do that on mathematica?
8
votes
3answers
269 views

Creating new List by comparing 2 lists elements

Suppose I have two Lists (Not equal length). Both contain random numbers between 0 to 5000 (or another max limit): ...
4
votes
2answers
204 views

Flip sign of one variable in list

I have this list of x, y-pairs l={{x1, y1}, {x2, y2}, ...}. Now I need to flip the sign of the y values only before plotting. What is the easiest way to do this ...
2
votes
1answer
46 views

Extract part of list by reading it in a cyclic manner

I have trouble extracting part of a list in a specific order, say, increasingly in a cyclic manner. For example, I have the following list list={0,10,6,-5,-10} ...
2
votes
1answer
65 views

Why does `Position` by default return a list of lists of positions instead of a simple list of positions?

Position[{1,2,3,4,2,3,4,5},2] (* Output: {{2},{5}} *) Why does Position work this way? I understand this form might be ...
2
votes
7answers
329 views

How to repeat a matrix on it's side?

I have the following matrix in Mathematica: mat = {{0,0,1,1}, {0,1,0,1}} I want to repeat this matrix N number of times on the side. For example if N = 3 then ...
0
votes
0answers
19 views

General question about solving a large set of linear equations efficiently

In my research, I got a large set of linear equations, about 10 000 equations with more than 10 000 variables. It is not efficient to use "Solve", so does anyone know any way to solve the equations in ...
2
votes
3answers
147 views

Selecting lists from lists of lists

I have the following list: points = Tuples[Range[0, 1.25, 0.25], 9] I would like to select only those lists who have the following properties, naming the ...
0
votes
5answers
156 views

How to expand a MxM matrix with replicates of itself and drop some of the rows and cols periodically?

How can I expand a 2d-matrix with dimensions x,x (e.g. mat = {{ 1, 2 }, { 3, 4 }}) with replicates of mat into ...
7
votes
1answer
102 views

Generalizing LongestCommonSequence to 3 or more arguments?

The function LongestCommonSequence finds a longest common subsequence between 2 lists. Apparently, this built-in function does not accept more than 2 arguments. How ...
4
votes
6answers
423 views

Easiest way to extract the coefficient of a polynomial

For a term in a polynomial, say 387 a1^4 a2^3 x^3 y^7 z^100 w^364 What is the most efficient way to extract the coefficient of this term, i.e. 387?
3
votes
2answers
119 views

Creating a Random list with constraints

I need something similar to the List below, but not totally random and values within each individual column and row remaining the same: ...
3
votes
1answer
75 views

List of first elements

I have a list whose elements are (symbol or list) and I would like to replace the inner lists by their first elements. I do this ...
3
votes
2answers
66 views
3
votes
3answers
226 views

How to switch between a binary number as String and a as a list of digits?

I was trying with String Functions and I viewing any posts and have no results I want to know 1.- From cromo33 = Table[RandomInteger[], {i, 1, 33}] cromo33 ...
0
votes
1answer
24 views

Question about loading data by skipping

. It is often important to take data and measurements and give them a name which has a number, and manipulate them in a for loop fashion to manipulate a large data base efficently. The loop above ...
3
votes
1answer
49 views

Returning maxima of multiple sets

I am trying to prove a conjecture which involves the SetParitions[n] function (which requires the Combinatorica package). This function returns a list of all the set partitions of n. I'd like to take ...
6
votes
1answer
496 views

Does Mathematica have a functional programming idiom to loop over a list till a condition is met? [duplicate]

The module below takes a list of integers and performs fadic addition on it (if a bit slowly). ...
3
votes
0answers
69 views

Mysterious Riffle::rspec warning

I have part of a code that looks like this: ...
1
vote
1answer
87 views

Automatically generate and manipulate variables in Mathematica

First line is just loading data from a txt.file, so that i get two lists {f1,f2,f3,..},{laser1,laser2,laser3,..}. How can I do the same thing as above in just one line? i.e. I have a list of laser ...
1
vote
2answers
105 views

Filtering and summing sublists with Cases

I've declared a list: list = {{1, 2}, {2}, {3, 4, 1}, {5, 4}, {3, 3}, {a, b, c}, {e, f}, {g}, {}, {Sin[a], Cos[b]}}; now I've made an rule which add 2 pairs ...
2
votes
0answers
36 views

How to delete lines containing specific values from a matrix? [closed]

I am doing some numerical computations and a few iterations return values that are obviously incorrect (some numerical integration problem, I suppose.). I have managed to set these values to zero but ...
2
votes
0answers
25 views

Matching list entries by two values, adding the third [duplicate]

I have data in form of: data={{1,1,3},{1,1,6},{2,1,7},{2,2,4},{2,1,1}}; I want to match the entries with the same first two elements and add the third element in ...
1
vote
0answers
42 views

Select and use only one solution in a list solutions [closed]

I would like to use and plot only one of the two solutions of a quadratic equation. In particular this is my equation ...
0
votes
3answers
85 views

Interactive Application using Manipulate for Fibonacci Series

I am working on creating interactive app using Manipulate function on fibonacci series using SeriesCoefficient. I want to plot the fibonacci numbers based on the slider of Manipulate function. I ...