Questions tagged [list-manipulation]

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

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5
votes
2answers
146 views

change order element of a list in a particular order [closed]

I have this list : {0, 1, 2, 3, {0, 1}, {1, 0}, {1, 2}, {2, 1}, {2, 3}, {3, 2}, {0, 3}, {3, 0}} I would like to transform it with the following pattern : ...
2
votes
1answer
171 views

Diagonal matrix command in Mathematica

How to find the corresponding Mathematica commands for diagonal matrix operation in Matlab, e.g. AA=rand(3,3); Step 1.) finding the diagonal elements, and export ...
1
vote
2answers
34 views

A list of the exponents of the irreducible factors in a factored polynomial

I have a list of factored polynomials: {x^3, x^2 (1 + x), x (1 + x)^2, x (1 + x + x^2), (1 + x) (1 + x + x^2), 1 + x^2 + x^3, 1 + x + x^3, (1 + x)^3} I want a ...
4
votes
1answer
53 views

Best way to write a function that randomly takes definition from list of functions?

I want to define a function based on a random choice from a list of possible functions. For example, suppose the possible functions are {Sqrt,Log}. Then I want to ...
1
vote
1answer
91 views

Problem with fitting

If I have the following data (I have updated the data): ...
1
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0answers
73 views

What is “Flatten” doing to my elements?

Here's some of my code. x1 results in returning the position of a list in a {{{n1}},{{n2}}...}. Im trying to flatten it such that the list reads out as {n1,n2,n3....} some how it's adding elements. ...
1
vote
1answer
85 views

How to merge two DateObject list together?

I have two huge lists of flight data(one is around 7 million observations and another is around 1 million). The first one contains the city names, the departure time(accurate to the minute), and some ...
2
votes
1answer
85 views

Fitting an equation to data

If I have the followind data: data={{45, 2.93495}, {50, 2.94697}, {55, 1.9801}, {60,0.734437}, {65, -0.0128219}, {70, -0.695535}, {75,-1.35939}, {80,-1.47567}} ...
2
votes
1answer
42 views

alternative approaches to selecting elements from two vectors conditional on a third

The following will convey the idea: build a new vector based on an existing condition (boolean) vector. For simplicity, I'll build the conditioning vector (cond) in ...
0
votes
1answer
59 views

Periodic PaddingLayer

The possible values to specify the Padding option of a PaddingLayer include a fixed value, ...
4
votes
2answers
74 views

Subtracting one list of lists from another

I have two lists of lists, like: ...
2
votes
2answers
45 views

How to merge lists if first element is the same in both lists

I want to join sublists if first element is shared. Input ...
0
votes
0answers
42 views

Monospacing variable-width fonts

In some (older) discussion forums, you are limited to a specific variable-width font that can't be changed. As a result, tables get messed up. Example: Bananas 588 Egg 111 Arctic Cucumber 810 How can ...
1
vote
1answer
59 views

Replace Square Brackets with Curly Brackets [closed]

I have a dataset like this (imported from .csv file): {[1,2,3,4,5],[6,7,8,9,10],[11,12,13,14,15]} I want to replace all square brackets with curly brackets like ...
1
vote
1answer
81 views

Area bound (divided) by the y axis and a list data

I have an array of points in two dimensional plane, say A={{x1, y1}, {x2, y2},..., {x2000, y2000}}. The closed-loop formed by these points (by joining each point ...
3
votes
1answer
76 views

Command to make all items on the list functions dependent on a given set of variables

The title basically. A typical example is the co-ordinates of a particle, and I want to introduce time dependence to define it's trajectory. For example, if I have ...
1
vote
0answers
48 views

Problem using KarhunenLoeveDecomposition

I have a matrix called stochasticData.mat which size is 211302*50 and I need to perform the Karhunen-Loève decomposition on it to calculate the uncorrelated random variables. Note that stochasticData....
3
votes
1answer
46 views

Summing list elements for given index tuple

Is there a more compact way of summing certain elements of lists together when given a tuple of which elements to sum. For example if I am given the list of size 8: ...
1
vote
0answers
43 views

How to apply percent error to list of data [closed]

Say I have a list of data. data = {1,2,3,4,5} and those data values were measured with an instrument that has a listed 3% error. I can apply this per value with ...
0
votes
1answer
68 views

How to convert decimals to integers and joint them to a string for exporting

There's a list such as {0.1,2,0.15,5}. I want to know how to convert the decimal to integer( but begin with zero 0), and don't ...
0
votes
2answers
101 views

listing of vectors satisfying some special constraint

We have list = {{1, 1, 0}, {1, 0, 1}, {0, 1, 1}, {-1, 1, 0}, {1,-1, 0}, {-1, -1, 0}, {-1, 0, 1}, {1, 0, -1},{-1, 0, -1},{0, -1, 1},{0, 1, -1},{0, -1, -1}} ...
1
vote
1answer
111 views

Number guessing game to 1-100

My code is ...
0
votes
0answers
54 views

How to convert Symbol to Number?

Question I have a variable x which is associated with the number 1 : x= 1 In the program, I faced with the data type problem ...
0
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4answers
111 views

Flatten outermost parenthesis

If I have the following data: ...
3
votes
3answers
526 views

Connecting the closest points on circles with a line

Suppose I have the function f[c_, z_] := z^2 + c and the following collection of circles in the plane. This is a simple example with only three circles, disjoint ...
0
votes
1answer
73 views

Correlation test for $x$ and $y$ values of a list

If I have the following data: ...
0
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1answer
35 views

Solve multiple equations with a parameter by means of Reduce

I have developed a program that solves an equation and give its solutions as outputs: ...
7
votes
5answers
614 views

Changing sign of elements of a list on even positions

I have a list of lists of equal sizes (odd or even), e.g. list={{1,-2,3,1,3,4},{3,5,6,-1,9,0},{1,-2,-4,-5,1,5},{1,-1,2,3,5,4},...} I would like to change signs of ...
13
votes
2answers
462 views

GroupBy sometimes deletes values

GroupBy[{1, 1, 1, 1, 1, 1}, # > RandomReal[{0, 2}] &] sometimes returns something like ...
0
votes
1answer
52 views

Take value from Root that comes from Reduce

When I try to solve a transcendental equation such as $e^{-2x}+e^{-3x}=x$ with Reduce I use the following: ...
2
votes
1answer
46 views

Separating list with nested sublists of different lengths

Consider the following list, with sublists of different lengths ...
1
vote
1answer
36 views

Difference on average of y-axis between data sets

How can I calculate in Mathematica the difference on average between the y-axis of two data sets such?: ...
0
votes
0answers
35 views

Smooth ListLinePlot with missing elements in list

Consider the following list: {{1,1},{2,2},{3,3},{4,4}} Plotting with ListLinePlot gives a smooth linear curve. How can the list ...
0
votes
1answer
37 views

Classifying sorted sublists using union

I'm trying to classify a list according to its sorted sublists. For example: ...
1
vote
1answer
42 views

Delete Duplicates by a distance test

Consider the following list which is of length 245: ...
2
votes
1answer
73 views

Null being added to every element in list list

I recently just started using mathematica, and I'm having some trouble figuring out what's wrong with this. When I run this, the output I get adds Null with every element. I have no idea what I'm ...
0
votes
0answers
34 views

ListPlot and ListLinePlot not working for imported files

I have a for loop which is supposed to generate a bunch of different values. I then exported these values in a file from which I am trying to extract and plot the data. I use ...
0
votes
0answers
28 views

Saving data from for loop to file and then read the data and plot graphs

I have a for loop which generates random matrices, then performs a few calculations to yield a bunch of different values. Essentially, something like so: ...
1
vote
1answer
115 views

check a sequence in Pi

I read that the string 36541622473 occurs in π(pi) at position 36541622473, counting from ...
10
votes
4answers
685 views

Replacing duplicates instead of deleting them

My code replaces each repeated element by "X". ...
4
votes
4answers
121 views

How to find the repeated elements in a vector

Is there a way to write a function where the input is a vector and the output is the elements in the vector that are repeated? I was trying to use something along the lines: ...
0
votes
0answers
47 views

Find fit for 3D data

Consider some dataset in the form {x,y,data[x,y]}: ...
3
votes
1answer
202 views

Is there a command which applies Position[] to each element in a list? [closed]

Given a list of elements, I want to produce something similar to Tally, but instead of counting how many times each element occurs in the list, I instead want a ...
7
votes
2answers
137 views

joining three lists to plot data with errors

I have three lists: x = {x1, x2, ...}, y = {y1, y2, ...}, yErr = {y1Err, y2Err, ...} that I want to join into the following format: ...
5
votes
6answers
404 views

Count number of balls in each bin, given a two-element sequence of balls and bins

If I have a list: {ball,ball,BINDIVIDER,ball,ball,ball,BINDIVIDER,BINDIVIDER,ball,BINDIVIDER,ball} The balls and bins can be in any permutation. Then, the ...
1
vote
1answer
47 views

Table/list: find the last real number element of each row to constitute a list

I have a list (Table), mostly composed of real numbers. The list also contains some non-real elements. The list is similar to the following (but much much larger): <...
0
votes
1answer
32 views

can i create a variable which is a list and the values given as placeholders?

I have a bit of a weird question: I have a program which I transformed from an old Mathcad Program written by someone else which is a hot mess. It uses a bunch of constants in lists as inputs in ...
1
vote
2answers
37 views

Replace points on a grid with numbers to maintain order

I am DMing a game of DnD and one of my players is really into fear effects, which is cool, but the effect of having monsters suffer from the "panicked" condition gets tedious to render via ...
0
votes
1answer
20 views

y values of a list into the x values of another list [closed]

If I have two lists such as: ...
0
votes
1answer
45 views

How to plot a function when we want to change the independent variables? [closed]

Suppose we have two functions $z(x)=x^4+1$ and $y(x)=x^2+x+1$. Then how to plot $z$ vs $y$ (assuming in general that $z$ can not be written explicitly in terms of $y$)?