Questions tagged [list-manipulation]
Questions on the manipulation of List objects in Mathematica, and the functions used for these manipulations.
9,653
questions
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How to apply the Manipulate function on a 5D data set and visualize the data using ListContourPlot? [closed]
Say you have a data set with 5 columns and each column is defined by the variables theta, phi, x, y, z such that data(theta, phi, x, y, z).
I would like to use the Manipulate function on this list and ...
- 323
3
votes
5
answers
184
views
Importing Specific Data from a Text File
I am quite new to Mathematica. I have a text file that upon importing has a repetitive structure with characters included. I need to extract only the following in numbers only (no letters, dash lines, ...
- 33
4
votes
4
answers
211
views
How to tally a list of lists only by considering the first element of the sub list
We need to Tally a list of lists only by considering the first element of the sub lists and then sort the resulting list.
As a simple example consider
...
- 159
4
votes
5
answers
141
views
How to implement this zip function? zip[g,{f[{a,b}],f[{c,d}]}] to f[{g[{a,c}],g[{b,d}]}]
I have a function that returns an expression in the form f[{a,b}], and I use this function twice and assemble the expression ...
- 730
5
votes
4
answers
241
views
Select elements from a list based on alphabetical order criteria
I have this code to generate the anagrams for a 6 letters word:
...
- 1,544
3
votes
1
answer
98
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How to sum over Slot inside MapThread
I am trying to do simple operations with several lists. In this context, I was wondering if a sum over Slot is possible inside ...
- 1,897
3
votes
0
answers
49
views
How can I access subsets in manageable chunks?
I have a large subset (as an example).
subset = Subsets[Range[8000], {2}]
I cannot evaluate this as I don't have enough space.
So the question is how can I access ...
- 723
2
votes
1
answer
163
views
0
votes
1
answer
54
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Build 2D lists of functions and variables in different combinations
Can someone give examples on how to build 2D Lists of function and expressions by the given vectors? I have the following:
V1={a,b,c}; V2={1,2,3}; V3={x1,x2,x3};
...
- 346
2
votes
4
answers
222
views
How to convert the form of a solution from solve {x -> 1, y -> 1, z -> Sqrt[2]} into a list form {1, 1, Sqrt[2]}? [closed]
How to convert the form of a solution from solve as follows:
{x -> 1, y -> 1, z -> Sqrt[2]}
into a list form
...
- 4,884
5
votes
2
answers
180
views
How to select right triangles and non right triangles given their coordinates
I have a list of triangle coordinates in 2D-space:
...
- 1,265
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0
answers
51
views
How to convert RowBoxes into list of math expressions?
I have following RowBox which represents Step By Step solution of undefined integral
...
- 1
4
votes
1
answer
76
views
Flattening nested data generated in a table
The data in the following is structured like this $\{\cdot,\{\cdot,\cdot\}\}$, but I need it like this $\{\cdot,\cdot,\cdot\}$. How do I do this?
...
- 521
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1
answer
47
views
0
votes
0
answers
67
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JacobianMatrix function flattens input in column order
The JacobianMatrix function appears to flatten its input in column order. Both of the following queries (Wolfram Alpha syntax) give the same result:
Q1: "JacobianMatrix of {{a_1+a_2, a_1+ a_2, ...
- 1
-1
votes
3
answers
98
views
How to generate an array with specific conditions?
To randomly generate an array of 10 non-negative integers with a mean of 3 and a variance of 2.
...
- 4,884
0
votes
1
answer
48
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Syntax regarding Manipulate plot with multiple functions
I am facing the following issue; I have the solution of a ParametricNDSolveValue and would like to plot several solutions with varying parameter in the same Manipulate to see qualitative differences. ...
- 115
4
votes
2
answers
323
views
Get cumulative sums in a list without using a for loop [closed]
I want a list of the kind list = {a,a+b,a+b+c} for list plotting. The quantities of the list come from a function. Let us say this is
...
- 411
2
votes
1
answer
81
views
Find disjoint subsets and their union is {1...9}
I have such a list
sets = Select[IntegerDigits /@ (Range[Floor@Sqrt@987654321]^2),
DuplicateFreeQ@# && FreeQ[#, 0] &]
I want to pick all subsets of ...
- 243
0
votes
0
answers
39
views
Writing list as disjoint union of input lists
Suppose I have two lists,
s1={{1,2,3},{3,1,2},{3,1,2},{2,3,1},{3,2,1},{1,3,2}}
and
...
- 101
1
vote
0
answers
34
views
Efficient chain rule implementation
(there is a fair amount of context here) I am implementing a generalized chain rule to do some work, say for order 3 in derivatives ($\partial_i = \partial/\partial x_i$):
\begin{align}
\partial_i \...
- 669
5
votes
2
answers
519
views
Fill a matrix with randomly placed elements that are a certain distance apart
Problem statement
I want to populate a matrix of points with randomly placed elements, here denoted as x. In all matrix rows there must be an equal number of x-...
- 82.6k
6
votes
5
answers
377
views
Combining duplicate elements in a list
I have a list of the form,
mylist = {{0.1, 1.2},{0.3, 2.1},{0.1, 0.5},{0.4, 0.4},{0.4, 0.1},{0.1, 1.6}}
I would like to create a function, ...
- 1,533
0
votes
2
answers
56
views
How to use FoldList for matrix multiplication?
I'm trying to use FoldList to create successive matrices that depend on a changing parameter n, so the transition matrices are ...
- 27
5
votes
1
answer
170
views
How could I speed up this tensor product?
I have to take tensor products of lists of tensors and I want to include the possibility of tensors whose components have high working precision. The tensors are all totally symmetric, so the first ...
- 669
2
votes
6
answers
284
views
How can I find all the different ways to group integer numbers from 1 to 10 into 3 lists?
(Unfortunately, I couldn't change the bounty message. By n above I meant the number of sublists.)
How can I group a list of integers from 1 to 10 into 3 sublists of ...
- 723
1
vote
1
answer
54
views
How to convert a list of polynomials with different degrees into a list of lists?
I asked a question about converting a polynomial into a list.
Now I have a list of polynomials. For example,
...
- 371
5
votes
4
answers
313
views
How to convert a polynomial into a list?
I have a list of polynomials. Each polynomial looks like:
p[1, 2, 5] p[3, 6, 9] p[4, 7, 8] - 3 p[1, 2, 4] p[3, 6, 9] p[5, 7, 8]
How to convert each of these ...
- 371
4
votes
2
answers
220
views
Reverse association and map through its values/keys
I suspect this could be done in a shorter and more readable code:
Challenge: do it without Normal and Association.
...
- 21.4k
0
votes
2
answers
82
views
Generating lists where new elements depend on the previous element
I am interested in using some type of list or table in-built Mathematica function to generate a list, where the elements of the new list not only depends on the input values of a previously defined ...
- 271
6
votes
5
answers
333
views
How to create sublists of a list based on the relation between their elements?
I have a large data set looking like this:
...
6
votes
5
answers
484
views
How to remove extra brackets from a list?
I have a list which looks like the following:
list1={{{a,b,c},{a1,b1,c1},{an, bn,cn}},{{f,j,k},{f1,j1,k1},{fn, jn,kn}}}
And I need it to be as follows:
...
9
votes
5
answers
387
views
Reconstruct list from its PositionIndex
Is there a more elegant or shorter way of reconstructing a list from its PositionIndex?
The following I regard quite cumbersome:
...
- 21.4k
3
votes
4
answers
174
views
Sort Column as a Row
I have
a = {1, 2, 3, 10};
b= {2, 3, 4, 8};
t= Do[If[a[[i]]+b[[i]]>3,Print[a[[i]]],"No"],{i,1,4}];
2
3
10
I need to get the result; t={2,3,10}
- 107
8
votes
5
answers
361
views
Element-wise vector-matrix exponentiation
I would like to exponentiate the vector x = {x1,x2} element-wise with the non-square matrix A = {{1,0},{1,1},{0,1}} so that the ...
- 83
11
votes
5
answers
522
views
Isomorphic lists
Is there a function that outputs True if lists are isomorphic (there exists a rule that changes the first list into the second one and inverse of the rule changes ...
- 21.4k
3
votes
3
answers
173
views
Generating permutations where no item appears in its original position [duplicate]
Given a Range[n] list, I need an algorithm that takes a permutation and output the next permutation. These permutations have the property that every item is ...
- 691
0
votes
0
answers
32
views
Evaluating determinant with entries from ./ output
I generate 16 values (this is a differential equation shooting method problem) from this kind of evaluation,
y41 = Evaluate[y4[tf1] /. torsolve4];
When I use them in Det[], it does not work because ...
- 1
2
votes
1
answer
48
views
How to quickly join in the following way? [duplicate]
Consider the following table:
tab = RandomReal[{0, 1}, {10, 3}];
subsets=Subsets[tab, {2}];
How to quickly reduce subsets to a ...
- 5,927
6
votes
3
answers
254
views
How to quickly join in the following way?
Consider the following table:
tab = RandomReal[{0, 1}, {10, 3}];
subsets=Subsets[tab, {2}];
How to quickly reduce subsets to a ...
- 5,927
6
votes
3
answers
177
views
Use sequence-functions to find certain sublists
I want to split a list of positive Integers into sublists whose
ascending elements differ by 1.
list = {1, 0, 1, 0, 1, 4, 5, 6, 5, 8, 1, 2};
This can be done ...
- 82.6k
2
votes
3
answers
107
views
5
votes
3
answers
127
views
Tally elements in a list of matrices up to an overall sign
I have a list of matrices like the following one with 6 elements:
...
- 115
1
vote
1
answer
109
views
Map array of functions
What is the most elegant way of mapping an array of functions to an array of arguments of the same length? In practice I want to map {f1,f2,f3} and ...
- 73
5
votes
3
answers
277
views
Searching for a list in a list
I want to see if a specific list is part of another list and get either True or False.
As an example:
...
- 187
2
votes
2
answers
52
views
Do one calculation over the whole list [closed]
I am trying to calculate the numerical residue of the function, but I want to perform it at the whole list and as a return. For example, let's take
...
- 133
0
votes
0
answers
18
views
How to remove part of a plot range between the data? [duplicate]
Is there a way to manipulate a plot range to be non continuous?
I mean, I have some data that goes from x=18;;25 and then x=45;;50.
I want to plot the in the same ListPlot, but if I do so there's a ...
1
vote
2
answers
57
views
Multiple assignments of items of a list [closed]
Suppose to have a list of items and two lists of indexes that are parametric and for example are:
l={2,3,5,7,11,13,17}
i1={3,4,7}
i2={4,7,3}
I need a clever code ...
- 691
7
votes
1
answer
125
views
DuplicateFreeQ VS UnsameQ
What is the exact difference between
DuplicateFreeQ @ arr and UnsameQ @@ arr ?
I checked on many examples and found no ...
- 1,904
1
vote
1
answer
89
views
How I can write the equation of the line as diameter of this circle?
I have this code.
ClearAll;
pI = {-1, -2};
pM = {x, y};
myr = 25;
list = {x, y} /.
Solve[{(x - pI[[1]])^2 + (y - pI[[2]])^2 == myr^2}, {x, y},
Integers]
I ...
- 1,680