Questions tagged [list-manipulation]
Questions on the manipulation of List objects in Mathematica, and the functions used for these manipulations.
6,406
questions
0
votes
1answer
78 views
correct use of the command FindInstance
I have tried to solve this system for numbers that go from 1 to 10 non-repeated integers, this occurs to me
...
1
vote
1answer
30 views
Counting the number of occurrences of specific values in a list in specific intervals
If the variable "digits" contains 10,000 digits from 0 to 9. How can the number of occurrences of 1s and 2s be counted in every 1000 digit intervals, that is to say the number of 1s and 2s ...
22
votes
8answers
4k 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
...
3
votes
2answers
56 views
Building a matrix from the columns of others
A is a n x m matrix, B is a matrix p x m, I wish to build C from appending the ith column of A and ith column of B, for all i ...
3
votes
1answer
70 views
Using DateListPlot without connecting dots
I have a list of values like this:
When I plot this data using DateListPlot[data] I get a plot connecting the individual points such as:
My question are:
How can ...
9
votes
2answers
56 views
Use Cases with empty cells in the list
I work with a complex dataset. The most simple form of this list looks like:
dat1 = {{a, b, c, {}}, {d, e, f, {1}}, {h, i, j, {2}}}
I want to select the nested {} ...
3
votes
3answers
97 views
Find rules for the similar “Conway's Game of Life”, and initial input on an 11x11 torus board. Descripted on the “Puzzel Chalenge IBM May”2020"
I solved on May 2020 this using mma . I am aware of
this command - Cellular automata.
But I can't use it on this challenge, because there's no concept of "Torus" in the CellularAutomaton . ...
16
votes
7answers
1k views
Find second largest elements in list
Given a list:
lis = {37.21, 37.21, 37.2, 44, 44, 44, 101, 101}
What is a simple way to extract the second largest elements?
...
0
votes
1answer
135 views
Fast way to count distinct pairs of integers
I have a association list, S, whose size is about 5*10^4. I also have a function F which takes in ordered pairs of elements from S, and spits out ordered pairs of integers. There is some amount of ...
1
vote
0answers
26 views
Thread::tdlen: Objects of unequal length in {{a,b,e},{c,d,f}} {x,y,z} cannot be combined
When I do the Times operation among list like this {{a, b, e}, {c, d, f}}*{x, y, z}, the error message is given as Thread::tdlen: Objects of unequal length in ...
2
votes
1answer
55 views
Finding points located in a specific locations of a 3D objects
I have the following list of points in 3D and would like to find the points which are located on the lower edge of the object and on (or closest distance to) the X-Y or Y-Z plane of the symmetry. (...
1
vote
1answer
53 views
How to manipulate solution outputs that appear in a list? [closed]
I have a list {E, {p, Ļ}}, and I need values E, p, and Ļ ...
4
votes
3answers
158 views
How to select radicand
Given
t1 = {1, Sqrt[2], Sqrt[3], 2, Sqrt[5], Sqrt[6], Sqrt[7], 2 Sqrt[31], 3, Sqrt[10], Sqrt[11], 2 Sqrt[17]};
I just want to get all radicands, which would yield
<...
1
vote
1answer
31 views
Exporting Nodal Surfaces/Minimal Surfaces as any 3D source (obj,stl,mb…)
I have been trying to export the surfaces that I gathered in the Wolfram Mathematica application,
So is there any way to export surface this to Maya,Cinema 4D, Rhino , or any 3D environment for 3D ...
2
votes
1answer
97 views
Finding lower boundary of a 3D object in list format
I have the following point list and would like to find the points located in the lower boundary of the 3D object (It is part of a body torso).
https://pastebin.com/L12n0Gfr
I am using the following ...
0
votes
0answers
56 views
Find a sublist with closest X and Y to a specific point in 3D
I have the following list of points and would like to know how I can find the sublist (i.e. point) which has a closest X and Y value to the X and Y value of a specific point (e.g here b1 ={{-20.6105, -...
5
votes
6answers
729 views
Partition list into $n$ sublists
Is there an inbuilt function/option or an elegant composition of functions for partitioning a list into exactly $n$ sublists? I played around with Partition and its ...
0
votes
1answer
41 views
How to change a list of values into variables? [closed]
I have a list {E, {p, Ļ}}, and I need values E, p, and Ļ ...
0
votes
1answer
56 views
Plot 2D into discrete 3D [closed]
I want to do a 3D plot of this functiony[x_, r_] = -Tan[r] x where I get a set of lines evenly distributed on the r axis, with a discrete distribution.
This is what ...
6
votes
5answers
291 views
Select lists where last elements are identical
Given the following list
t1 = {{5, 5, 50}, {6, 1, 37}, {6, 2, 40}, {6, 3, 45}, {7, 4, 65}, {7, 6, 85}, {8, 1, 65}, {6, 6, 72}, {7, 1, 50}};
I want to find those ...
1
vote
1answer
30 views
Replacing a submatrix of a matrix
Minding the fact that
In[102]:= {{1, 2, 3}, {4, 5, 6}, {7, 8, 9}}[[1 ;; 2, 1 ;; 2]]
Out[102]= {{1, 2}, {4, 5}}
is the upper left submatrix.
I would like to do the ...
0
votes
0answers
36 views
Binning of numerical 2d function [closed]
I have a set of data {x_i,y_i,z_i} organized as 3-member sublists in a large (~4000 sublists) list. The z_i are functions of (x_i,y_i): z_i = f(x_i,y_i), but the function f is known only numerically.
...
3
votes
2answers
294 views
1
vote
2answers
40 views
Substituting values from an association thread into a table of expressions
I have asked a question here. Yet I am trying to do the same procedure with AssociationThread Suppose I have the following function which is a normal distribution:
<...
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7,3642 gold badges14 silver badges35 bronze badges
5
votes
1answer
45 views
Substituting elements of lists into an expression
Suppose I have the following lists,
as = {1, 2, 3, 4};
bs = {10, 20, 30, 40};
and the following expression:
...
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7,3642 gold badges14 silver badges35 bronze badges
4
votes
1answer
77 views
Thread and RandomReal
I am trying to use Thread to apply a function involving RandomReal but it does not work as I expected.
If I have the function
<...
1
vote
1answer
85 views
How to use Quartiles to work the same as TI-83 calculator? [closed]
The statistics book I am using defines quartiles the same as Method 1 explained in wikipedia.
Use the median to divide the ordered data set into two-halves.
If there is an odd number of data points ...
5
votes
3answers
348 views
How to classify an ordered ascending {0, 5, 5, 10, 19, 22, 23} into several classes {{0,9},{10,19}, …}?
I attempted to classify an increasingly ordered list into several classes to make frequency distribution table. I am faced with a difficulty to nest two pure functions: one for ...
0
votes
1answer
52 views
How do we list all points in the Middle $3/7$-th Cantor Set?
Suppose we were to list all points in the $3/7$th Middle Cantor set where we first remove $3/7$th of $[0,1]$:
$$[0,1/7]\cup[2/7,3/7]\cup[4/7,5/7]\cup[6/7,1]$$
then $3/7$th of remaining intervals, $3/7$...
4
votes
3answers
86 views
2
votes
2answers
107 views
How to program a situation like the following in mathematics and generalize the process to other configurations?
Distribute the numbers from 1 to 10(view image) so that the sum of each row and each column is the same and
a) the maximum possible
b) the minimum possible
(I put it from 1 to 10 for ease)
I know it ...
5
votes
1answer
83 views
How do you take position “x” in multiple sublists to make a new list?
this is a rather rudimentary question, but I was wondering if there are more efficient ways to do the following:
dd = {{{12, 3, 5}, {14, 10, 11}}, {{15, 76, 65}}}
...
1
vote
1answer
36 views
Precisión of the numbers inside a list
I'm trying to become a List like this
list={1.34,2.64,5.098,6.432}
in a list where the numbers have precision of one digit, like this
...
21
votes
8answers
3k views
Shuffle product of two lists
I want to do the following: I have two lists {a_1,...a_n}, {b_1,...,b_n} and I would like to build now all shuffles out of this. This means all unions of these ...
3
votes
4answers
153 views
9
votes
2answers
2k views
How to optimally solve and generalize this Conway's Game of Life puzzle
I tried solving this using mma. I am aware of
this command - Cellular automata.
But i don't want to use that coz then there is no challenge.
So below is how i did it and my question is can this be ...
4
votes
4answers
325 views
How to find the smallest position of an element of an ascending list {1,4,10,12,20} such that the element is not less than 11?
Assume I have an ordered, ascending list {1,4,10,12,20}.
I want to find the smallest position of an element of the list such that the element is not less than 11?
...
2
votes
2answers
59 views
7
votes
2answers
2k views
All possible topological orderings of a graph
TopologicalSort[] returns one of many unique orderings.
From wikipedia:
if a topological sort does not form a Hamiltonian path, the DAG will have two or more valid ...
4
votes
2answers
83 views
Selecting elements of a list based on specific elements of their sublist
I have the following list
...
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7,3642 gold badges14 silver badges35 bronze badges
3
votes
1answer
63 views
How can I iteratively add elements to a list
Basically I want to make a histogram with a list of dates by using DateHistogram[]. However I have the data of the dates in nested list format, with elements like ...
6
votes
3answers
106 views
How to get elements corresponding to UpperTriangularize
For a generally non-square matrix M, I want the upper triangle that include the diagonal entries. Specifically, this is implemented via UpperTriangularize:
...
5
votes
2answers
97 views
How to permute elements in a list
I am attempting to decrypt a ciphertext. I split the cipher into blocks of five, and now I want to permute each individual block. My goal is to be able to permute each individual block by the same ...
12
votes
1answer
921 views
Is there any better way to create {a, a, a, b, b, b, b, b, c, c} from {{a, 3}, {b, 5}, {c, 2}}?
My attempt:
data = {{a, 3}, {b, 5}, {c, 2}};
output = Table[#[[1]], #[[2]]] & /@ data // Flatten
{a, a, a, b, b, b, b, b, c, c}
0
votes
1answer
47 views
How can I add a different value to each item in a list?
I am trying to decrypt a modified VigenĆØre cipher text. I am unfamiliar with Mathematica, so I need some guidance. Here is what I want:
...
1
vote
4answers
743 views
Percent Difference between elements from 2 matrices
If i have a 22 by 25 table of values which depend on n and r, and a list of values that depends on r that is a 22 by 1 matrix, how can I find the percent difference between each element, by row in the ...
1
vote
1answer
45 views
Scan and Set over multi-dimensional data
Suppose I have the following:
Table[x[i,j] = f[i,j], {i,1,10},{j,1,10}];
I want to set variables x[i,j] to have value ...
6
votes
1answer
366 views
Why can't I create {a,a,a,b,b,b,b,b,c,c} from x={a,b,c}; f={3,5,2}; Thread@Table[x,f]?
ClearAll[x, f]
x = {a, b, c};
f = {3, 5, 2};
Thread[Table[x, f]]
produces
Table::nliter: Non-list iterator f at position 2 does not evaluate to
a real numeric ...
3
votes
3answers
378 views
Inserting an integer into a sorted list
I'm wondering if inserting an integer into a sorted list (in a way that the list remains sorted) can be performed in Mathematica in some fancy way in $\log(N)$ time?..
The question was asked here, ...
2
votes
3answers
33 views
Appending a list into another list at various levels [duplicate]
I have a list with three levels.
list = {{{7, 5, 8}, {4, 8, 9}, {7, 0, 1}, {3, 0, 4}, {5, 1, 2}}};
And I want to put in a list {e,x,y} at the end of every element.
...
