Questions tagged [list-manipulation]
Questions on the manipulation of List objects in Mathematica, and the functions used for these manipulations.
0
votes
1answer
48 views
Breaking up a list of lists
I have a list of values stored in SortedLat, where SortedLat is a list of 74 sublists, and each sublist has its first element be a string. As you can see I am trying to create the first column for a ...
0
votes
0answers
37 views
How to process the list of photos?
We have a list of photos (about 300) and we need to apply to each photo the function ColorSeparate, but when we do, it tells it can process just one at a time.
The whole task is to define how fast ...
0
votes
0answers
53 views
4
votes
2answers
81 views
List of lists elementwise greater/smaller than
I have two lists
a = {{3,1,2},{5,1,3},{4,1,1}}
b = {{4,0,3},{4,2,2},{5,0,2}}
And would like to compare each element within
...
2
votes
3answers
175 views
Find the 3D region containing the origin bounded by given planes
I'm writing a code to generate the Wigner-Seitz cell of the reciprocal lattice for a given set of lattice translation vectors. For example, consider the Body Centered Cubic (BCC) lattice whose basis ...
3
votes
3answers
138 views
6
votes
2answers
71 views
Merging two rows with rounding their first elemnts
Mathematica shows my data in the below style:
...
8
votes
2answers
1k views
Why does a table with a defined constant in its index compute 10X slower?
I need to do some iterative summations. Here is a minimum working example:
...
6
votes
2answers
133 views
Sorting upon the first element of a nested list and show that as numerical values
I wish to sort the below list upon the first elements:
...
0
votes
1answer
36 views
How to create a list of undefined functions?
I have a undefined function $\phi[i,j]$ where $i=0,1,...,m$ and $i=0,1,...,n$.
How can I generate this list:
{$\phi[0,0],\phi[1,0],...,\phi[m,0],\phi[0,1],\phi[1,1],...\phi[m,1],\phi[0,2],...,\phi[m,...
4
votes
3answers
203 views
3
votes
2answers
154 views
Applying FoldList to its own output
I'm trying to figure out a functional way to essentially apply FoldList (or some related function such as Nest or ...
2
votes
0answers
43 views
How to calculate a projection of x,y,z data to x any y plane?
I have a List containing x,y,z data, which I can plot nicely in a ListContourPlot:
...
-1
votes
1answer
45 views
Finding longest repeating sequence in a list of lists [on hold]
I want to find the longest repeating sequence in a list of lists.
...
-1
votes
0answers
27 views
Importing a rectangular .csv produces a nonrectangular dataset. Why? [closed]
I'm trying to import a large dataset from csv format into mathematica. As far as I can see, the dataset is rectangular in the csv, with no null values. But when I import it I get a list of lists of ...
3
votes
1answer
65 views
Applying dot product to list of vectors
Suppose I have:
w = {1,0}. I want to apply the dot product of w to each element of the list of vectors ...
0
votes
0answers
31 views
Counting number of words in a Wikipedia article [closed]
I tried using the command
Total[TextWords[WikipediaData["computer"]]]
but it didn't work. Why?
0
votes
2answers
47 views
Remove 0.*I in imported table
I imported some table containing elements with 0.*I. I tried to remove this 0.*I by using ./{"0.*I" -> 0}, however, it did not work. Could you please tell me how to remove it?
Edit. I created a table ...
1
vote
2answers
31 views
Partition singular series symmetrically into increasingly larger sub series
I've created a symmetric series with powers
$${-n,-(n-1),\cdots,-1,0,1,2,\cdots,n}$$
and wish to study the convergence of the series as a function of the number of symmetric terms. So I first ...
8
votes
4answers
245 views
Extracting sublists that contain similar elements
Let's say I have a list containing different sized sublists of string pairs structured like this
...
2
votes
2answers
118 views
How to turn a Python array into Mathematica List?
I am running
a = RunProcess[$SystemShell, "StandardOutput", "python2 fit.py"]
which returns
"[ 0.04044647 0.75243326 -0.42992283]\n[ 0.04163976 0.15076435 ...
3
votes
2answers
1k views
Create a list of all possible Boolean configurations of three constraints
I have three nonnegativity constraints
\begin{equation}
A_1>0, A_2>0, A_3>0.
\end{equation}
I want to create a single List consisting of all possible/inequivalent Boolean configurations of ...
2
votes
1answer
41 views
Turns nested Lists into nested Associations, ReplaceAll for list vs ReplacsAll for association
I want to transform some nested lists into nested associations except the "rows"->List pattern.
Here is the example
...
1
vote
1answer
25 views
Trouble with RecurrenceTable using elements from a previously computed list
When I use RecurrenceTable to solve a recursion relations, I encounter a problem, which is perhaps simple, but I do not understand why it is complaining. Here is a ...
5
votes
4answers
379 views
Looking for a simple way to manipulate one column of a matrix
Given
{{a, b}, {c, d}}
I want to get
{{c, b}, {a, d}}
with one simple expression. Is this possible?
1
vote
2answers
80 views
Selecting matrices based on existence of unique column and row of all equal terms
So, I have a list of lists of lists such as the following:
{{{4}},
{{7, 7}, {7, 7}},
{{5, 5}, {6, 6}},
{{2, 1}, {1, 1}}}
Interpreting the elements of this list ...
1
vote
2answers
120 views
Flatten a four dimensional array into a matrix
What is the simplest way to transform an array of the form
...
2
votes
1answer
18 views
What would be the best implementation of the D'Hondt method of highest averages for allocating seats on party-list proportional representation?
The 2019 European Parliament elections are happening shortly and seat allocation will use the D'Hondt method of highest averages. In order to analyse possible scenarios and results I need a Wolfram ...
1
vote
1answer
47 views
Dynamic Plot of multiple Disk Graphics
I want to plot multiple disks with disk-coordinates and disk-radii from two dynamically updated lists. I think there should be an easy way to do that but I dont get it. Thx for your help!
...
1
vote
3answers
55 views
Mapping a function with levelspec vs. Mapping over a flattened list
I have borrowed the following cyclic permutations list making function from here.
...
0
votes
1answer
23 views
Count the number of words in WordList that start with a “q” [closed]
How can I create a subset of WordList[] that contains only the words that start with "g"?
7
votes
3answers
271 views
TreeGraph construction
I have a list l={{1,1},{2,3},{2,3,2,3,4}}. Based on that list, I want to draw a tree. Starting from a single point at the top of a tree, I proceed as follows, using ...
4
votes
1answer
170 views
Transforming a list to list of lists using a specific rule
Say, we have a list: l = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14} and a corresponding list: v = {2,3,2,3,4}. We want to ...
0
votes
1answer
74 views
Part assignment is not a symbol [duplicate]
read some related posts and found no solution. For a list defined like this
m = {0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.9, 1.0, 1.5, 1.6};
when I define this function
...
0
votes
0answers
22 views
0
votes
0answers
65 views
How do you drop Undefined elements from a list?
Suppose v[w,y] is a function and consider the following solution for w:
solw = Solve[v[w,y]==0,w,Reals];
w[y]:= N[w/.solw]
I ...
2
votes
1answer
59 views
Counting elements of multidimensional list according to patterns
I have the tuples :
a = Range[0, 2];
l2 = Tuples[{a, a}]
which gives
...
3
votes
1answer
52 views
How to utilize a Pick[] command in a differential equation
The code below is a simplified example of a problem I am working on. I first define a relation V that depends on x[t] and ...
3
votes
1answer
64 views
Find intervals between elements of a list [closed]
If I have a list:
{a,b,c,d,e,f}
Is there a function that allows me to easily construct a list that shows the intervals between elements:
...
6
votes
5answers
374 views
Select list elements based on other list
I am trying to find a nice and clean method to select elements from one list which are in another list or the criteria is based on another list. The ones I want to returned are in ...
7
votes
5answers
470 views
Efficient deletion of specific list entries
It is sometimes useful to remove exactly the amount of specific entries on one list from another.
Consider:
...
11
votes
2answers
209 views
Selecting elements from a list where the order is set by another list
I have two lists, list A and list B. All of the elements of A are members of ...
3
votes
2answers
61 views
ListPointPlot3D filling between two lists
I'm trying to connect pairs of corresponding points from two lists in a ListPointPlot3D (similar to what was done here but in 3D). Filling-> {1->{2}} isn't ...
1
vote
5answers
98 views
Extracting certain elements from a ragged array
For the following let me use this notation:
$\qquad \text{data}=\{\{x_1,y_{11}\}, \{x_1,y_{12}\},\{x_1,y_{1N}\},\,\dots,\,\{x_2,y_{21}\}, \{x_2,y_{22}\},\{x_2,x_{2M}\},\,\dots\}$,
where $M\neq N$. ...
0
votes
0answers
39 views
0
votes
1answer
37 views
Finding the negative real root of in set of solutions under a varying constraint
Suppose I have a function and its derivative like:
V = x^3.5 - x*y
Vx = D[V, x]
I first solve V for ...
3
votes
1answer
68 views
Finding positions of minimum values in list
I would like to find the positions of multiple occurrences of a minimum value in a list. For instance, for the list {1, 2, 1, 3}, I want to obtain the two positions for the occurrences of the number 1....
9
votes
5answers
710 views
Building a list of products from the elements in another list
I'm new in Mathematica software, and I need help with a simple exercise.
Given the list
list = {x, 3.2, y, 1, 2.679, 3, z, 4, -7.9};
I need to make some rules ...
0
votes
1answer
44 views
Extract a single list of data points from a list of multiple lines
So I have a list of 50 lines that ive acquired using the EdgeDetect function on a .bmb from an experiment ive run. The list looks like:
...
4
votes
4answers
140 views
How to apply differences on part of a list and keep the rest?
I have a list,
l1 = {{a, b, 3, c}, {e, f, 5, k}, {n, k, 12, m}, {s, t, 1, y}}
and want to apply differences on the third parts and keep the parts right of the ...
