Questions tagged [list-manipulation]
Questions on the manipulation of List objects in Mathematica, and the functions used for these manipulations.
5,605
questions
4
votes
3answers
142 views
8
votes
3answers
250 views
Create Array from list of indices/values
Is there is a performat way to convert something like
{{0,0},a},{{0,1},c},{{1,0},d},{{1,1},e}
into
{{a,b},{c,d}}
The ...
5
votes
3answers
103 views
Coverting list of string into integers and reshaping the original list
I have the following list which I am importing from Pyhton - thus the format:
l = {{"a", "[1,2,3,4,5]"}, {"b", "[6,7,8,9,10]"}}
I wonder how can I covert this ...
6
votes
4answers
300 views
How to delete certain lists from a nested list?
I have a nested list as the following example (want to remove lists with same or incremented elements such as {1,2,3,4,5}, {2,2,2,2,2}, {1,1,1,1,1}):
...
5
votes
3answers
333 views
Mathematica function equivalent to Matlab's residue function (partial fraction expansion)
I am looking for a Mathematica function equivalent to Matlab's residue function.
If there is no Mathematica equivalent, I would like to write a function that given the coefficients of two polynomials ...
0
votes
0answers
48 views
How can I Joint two lists? [on hold]
I have two lists:
list1 = {a, b} and list2 = {c, d}. I want to joint two lists into a list ...
0
votes
0answers
37 views
Interpolation data in two variables
I try to interpolating the data Data = RandomReal[{0, 1}, {7, 7}] using the a[k_, j_] := Data[[k]][[j]]
for example
...
0
votes
1answer
40 views
unexpected Transpose::tperm error [on hold]
I am trying to use Transpose on the two lists of same length:
Mathematica code is
...
5
votes
3answers
125 views
Pure functions applied to a two dimensional list
Lets say I have a two dimensional list:
list = {{a, b, c}, {aa, bb, cc}, {x, y, z}, {xx, yy, zz}};
and two pure functions:
...
8
votes
4answers
315 views
0
votes
0answers
67 views
Efficient Mathematica Code for List Problem
Say we are given $f(m,n)=m \pm 2n + (-1)^n$ where $m>0, n>0$, $m$ as well as $n$ are integers. The problem is to generate a list of all the integers that will not be found in the list of values ...
5
votes
2answers
368 views
Turning arguments into exponents
I'd like to replace every instance of L[stuff], e.g.,
L[-1,-2,-2]
in an expression with ...
1
vote
2answers
82 views
Making conditionals in a function
I'm relatively new to mathematica, and need to make a function which takes a set of whole numbers as input, then iterates through all whole numbers and sorts them into two sets, one for numbers which ...
4
votes
1answer
51 views
4
votes
3answers
441 views
Generating random numbers that keep a minimum distance
I want to create a list of n random integers from 1 to m, where all integers have to be at least a certain distance min apart (i.e. 3 integers out of Range[10], keeping a minimum distance of 2)
...
0
votes
1answer
31 views
Make a nested list of variable size
I want to try to make a list of lists of variable length in the following way
...
4
votes
2answers
53 views
Making polynomials representing frequency of a character in a list
Suppose I have the following list:
l={{"a"}, {"a", "h"}, {"a", "d", "k", "r", "v"}, {"a", "b", "c",
"k"}, {"a", "b", "c", "s", "u"}}
this list made of the ...
6
votes
2answers
181 views
Extracting points from 3D plot that lie along an arbitrarily oriented line
Starting from i.e. the following 3d plot:
d = RandomReal[1, {100, 3}];
ListPlot3D[d]
Is it possible to extract points that lay along an arbitrarily oriented line,...
0
votes
0answers
71 views
How is this mathematical term called? [closed]
I need help in identifying the underlining mathematical term of my method (group membership of a Person to an ideal role)
So I have Ideal values (for the ideal role) shown here in the 1st column (...
3
votes
2answers
188 views
How to find the positions of replaced elements in a list
I have two sets of elements
a={3, 4.8, 5, 4.2, 3.6, 2.3, 4.5, 3.7}
b={2.8, 4.7, 5.3, 3.5, 4.7, 2.8, 4.2, 3.4}
and I create ...
6
votes
3answers
559 views
How to convert diagonal matrix to rectangular matrix
Suppose you have the following diagonal matrix:
$\left( \begin{array}{cc} a & 0 \\ 0 & \{b,c\} \end{array} \right)$
How can the above matrix be converted to the following rectangular one?...
3
votes
1answer
72 views
Delete elements less than the last largest element
Here is my list. The first column contains its index and second column has data.
...
0
votes
1answer
40 views
When tabulate numbers from a list Mathematica changes them?
I would like to tabulate a list of numbers but Mathematica slightly changes these numbers?!
Here is the list
...
0
votes
1answer
28 views
Defining a function that modifies a list [closed]
I have the a list A and I want to define a function f that takes out the $i$-th element from the list ...
0
votes
3answers
55 views
List manipulation: conditional result based on variable-length sublists, part deux
This is an outgrowth of this question.
Suppose I have the following definitions:
...
6
votes
3answers
224 views
Sorting a list according to some pre-specified rules
Given a list such as
{12,9,3,42,30,10,11,1,2}
I would like to place only the multiples of 3 in the natural order without changing the order of the other ...
1
vote
1answer
59 views
For loop for two variable at the same time
Can I use for loop for two variables as example show below at the same time?
for (int x = 0, y = 0; x < 10 && y < 10; x++, y++)
1
vote
1answer
47 views
Using ImplicitRegion over variable number of dimensions
I need code that creates a d-dimensional regions - where "d" varies. This simple example fails -
...
2
votes
1answer
35 views
Extracting list from a list of lists obtained using Solve function
After solving a set of equations I got a solution like the following using Solve[] function.
...
0
votes
0answers
61 views
I want to write $ k = \{k1,k2,k3,…,kn\} $. How could I do this? [duplicate]
When I write k = {k1, k2, k3, k4, k5}, it is ok. But I Want a general form, like k = {k1, k2, k3, k4, k5, ..., kn} how could I ...
1
vote
1answer
57 views
4
votes
3answers
105 views
Set the parent of each child while iterating over a List
I'm still new to this language and have tried a number of ways with no success. I have a list of keys with values. These values are used to identify the parent of the current item. The list is ...
4
votes
1answer
38 views
Merge overlapped intervals in a list
I have a list of intervals:
{{1,10},{8,15},{17,22},{24,36},{32,40}}
I want to merge overlap pairs. For example, the first and second pairs are overlapping, so I ...
0
votes
0answers
15 views
Set conditions on SingularValueDecomposition
I'm a new user of Mathematica, and I am having some issues with SingularValueDecomposition.
This function returns three matrices {u,v,w}, with v that is diagonal and u,w unitary such that u.v....
1
vote
1answer
32 views
Identification of linear combinations in a matrix
I have a matrix R which is having a dimension of 20 cross 20. When I extracted the rank of this matrix I got 16. I just wanted to which are these four rows are or columns which are dependent on each ...
1
vote
1answer
33 views
Phase choice for Singular Value Decomposition
I'm using SingularValueDecomposition to find the unitary matrices that diagonalize a given matrix (that I have). This decomposition is unique, up to multiplication for an arbitrary phase of each ...
2
votes
1answer
29 views
Plotting of ListLinePlot with proper legends and rendering
I have four data sets in the form {f(x),x} as, data1, data2, data3, data4.
Now, I am trying to plot the four datasets using ListLinePlot. But I'm not able to get ...
3
votes
4answers
591 views
List comprehensions in Mathematica?
I'm looking for an implementation of list comprehensions in Python (nested for-in statement with destructuring and conditionals). Here's an example:
...
2
votes
1answer
31 views
Picking elements of a list
Suppose I have the following list,
t = {{"e:r", "a", "p", "z"}, {"r:e", "a", "l", "o", "t", "y",
"z"}, {"j", "o", "z"}};
I want to go through it and pick ...
0
votes
3answers
64 views
More general permutation of lists
For some arbitrary $N$, I would like to construct all permutations of lists of length $n \leq N$ such that the sum of each permutation list adds to a value less than or equal to $N$.
Specifically, ...
2
votes
2answers
59 views
How to select the data in the following way?
I have the data which is obtained by joining the subsets with 12 rows. The subset has the following form:
...
3
votes
3answers
109 views
Is there an easy way to index by a binary vector / mask?
I would like to be able to extract elements from a list where indices are specified by a binary mask.
To provide an example, I would like to have a function ...
6
votes
8answers
2k views
Simplify the code
I have a function that grabs the second part of the list and change it to times,
...
2
votes
4answers
73 views
Replacing function depending on the number of summed elements in its argument
I want to replace function
f[x+y+z]
by
g[t]
but I do not want to touch
...
4
votes
3answers
91 views
Collect the elements from a list by categories [closed]
I have a list of elemets with different variables {a,b,c,A,B,C},
list={3 b, A Cos[c]^2 Sin[a] Sin[b], -a E^(I a c) f[C, A]}
Where f is some function. By assuming ...
4
votes
2answers
89 views
Sort a list of lists by increasing order of elements [closed]
What is the quickest way to sort a list of lists of integers, such that the first sorting criterion is the first element of the list, the next is the second element of the list and so on?
E.g. The ...
1
vote
1answer
35 views
4
votes
3answers
159 views
List manipulation: conditional result based on variable-length sublists
Suppose I have the following lists:
eqexp={a,b,c,d}
eqval={e,f,g,h}
signval={{},{1},{-1},{1,-1}}
I want to create a new list of inequalities, where the signval ...
3
votes
2answers
55 views
Picking elements from a list
That's must be a very trivial question. Suppose we have the simple list
data = {{-1, 0}, {0.2, 0.4}, {4, 0}, {0.3, 0}, {0.2, -0.4}};
Then, is there a quick and ...
6
votes
3answers
639 views
List Manipulation : {{{a,b},{c,d}},{{e,f},{g,h}}} into {{a,b},{c,d},{e,f},{g,h}}
Hi I'd like to transform the matrix :
...
