Questions tagged [list-manipulation]
Questions on the manipulation of List objects in Mathematica, and the functions used for these manipulations.
9,652
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Unexpected Peaks and Detours in PNJL Model Plot Using FindRoot
I'm working on a numerical solution for a PNJL model. The model I’m working on is based on the formalism described in this paper: arXiv:hep-ph/0506234. My goal is to reproduce plots similar to the ...
0
votes
1
answer
77
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Automate generation of new list [closed]
Suppose there is a list of lists as follows:
BigList={{1,2,3},{4,5,4},{7,7,9},{10,11}}
and it is required to apply a given command separately on each sublist ...
- 101
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103
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+50
Fastest way of removing outliers from a data set which depends on a variable
Edit: I meant $j\to\infty$...
Suppose we have the following code:
...
- 57
3
votes
1
answer
123
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Numerical precision of keys in Merge function
I'm trying to merge list member with the same numerical key values:
a = {53.8 -> x, Floor[53.81`, 0.2] -> y};
Merge[a, Total]
then I get:
...
- 305
3
votes
1
answer
109
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How to delete members of a list by rule [duplicate]
I have a list:
lis = {"a",1,""}
and would like to delete from the list all elements that consist of "" to give:
...
- 5,015
-2
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3
answers
80
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1
vote
1
answer
58
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Applying a condition to a column in a table using If
Let's assume we have the code below (The below code is derived from answer @DanielHuber link and answer @Domen link)
...
- 1,014
3
votes
6
answers
282
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`Drop` for list of elements of different dimensions
MWE is the following list
{{{1,2,3},4},{{a,b,c},d}}
I want to Drop the 3 and c here. (In reality, it is a very long list of ...
- 525
4
votes
4
answers
460
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How to raise a vector to powers contained in a vector, change the list into a product, and do this for all the lines of a matrix, efficiently?
I want to raise the first vector var to the powers in a second vector, and then multiply the list, when the second vector runs over all lines of a matrix ...
- 1,982
2
votes
5
answers
279
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How to find intersecting linear equations between two lists?
I have two lists of linear equations:
list1 = {x - y == 0, x + 2y == 0, 3x - y == 0}
list2 = {-x + y == 0, -x - 2y == 0, 3x - y == 0, 3x - 2y == 0}
I want to ...
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45
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How to solve numerically a fourth order BVP having a Boundary condition at Limit Approaches to 0
I have the following fourth order BVP (pde):
$\frac{1}{4}f_{yyt}+H^{4}(ff_{yyy}-f_{y}f_{yy})=\frac{1}{H^{2}R}(yf_{yyy}+2f_{yy})$
with boundary conditions:
$f(0,t)=0$, $f(1,t)=0$, $f_{y}(1,t)=-\frac{\...
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1
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Match list to a pattern [duplicate]
I want to match a list to a pattern, but MatchQ is not doing the job as needed. For example, I need:
...
- 575
4
votes
3
answers
341
views
Fourth order BVP partial differential equation
I am trying to solve fourth order partial differential equation describing a fluid problem, by using Mathematica. The PDE is provided here as:
$(1/4)f_{yyt} + H^4(ff_{yyy} - f_y f_{yy})=1/{H^2R(yf_{...
1
vote
1
answer
85
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How to generate all possible combinations subject to symmetry conditions
I have a list of 6 (possibly repeated) integers:
ints = {a,b,c,d,e,f};
and also a set of symmetry conditions:
You can switch the signs of elements 1 and 4 at the ...
- 575
3
votes
3
answers
202
views
Function to find the most common numeric ordered pairings (value, count)
Let us say that I have a list of numeric ordered pairs where the first number represents a value to be counted and the second number represents the count of that value. The following is one way to ...
- 121
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1
answer
38
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Add a new column based on the complement of column data in a table
I have this code to replace the data of each row in a specific function and display a new column showing the values of the function
...
- 1,014
1
vote
1
answer
59
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Finding the position of a list element using functions like Max on lists that might contain 'Indeterminate' values
I am working with lists of the following form:
...
- 121
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2
answers
76
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Best way to extend the size and add terms to a SparseArray without expanding
Let's say I have a "small" SparseArray of any size, in the example $2\times2$
...
- 37k
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49
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Operations on Sub Lists
Let us assume that I have the following list of lists:
foo = {{2, 1}, {3, 1}, {4, 1}, {2, 2}, {3, 1}, {2, 1}};
and that I want to multiply the elements of each sub ...
- 121
2
votes
2
answers
164
views
Union of lists with original order
I would like to combine a few lists such that the resulting list follows the order of the original lists, which will have disjoint elements, but their order is compatible.
...
- 1,112
1
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1
answer
80
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How to check equivalence when variables in equations are replaced by their negatives?
In a previous post about checking whether two systems of equations are equivalent, the suggestion was to use the Reduced Row Echelon Form, which was great.
However, I now want to consider an ...
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2
answers
81
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Reshaping a list as another nested list
I have the following list ( p to be some even number )
...
- 307
3
votes
1
answer
88
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Find positions of unique elements in a nested list
I have a nested list with depth 6. The items in the list are mathematical expressions. I want to find the positions of the unique items in the nested list. I have found the following, which works for ...
- 575
4
votes
3
answers
210
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How to make a list plot from a "vector array"?
I have an (excel) table where my first column have decimals from -3 to 3, and the other columns have associated values, in such a way that i have a "vector array" similar to this:
...
- 43
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1
answer
31
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Solving list manipulation exercise involving longest sequence of identical digits in a list using functional programming idiom
I have been trying to improve my list manipulation skills by doing some of the exercises in Wolfram's Intro book. I am struggling to solve this question using only functional programming constructs. ...
- 189
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3
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159
views
1
vote
1
answer
48
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Applying the binomial distribution to matrix data
The probability that a random variable $X$ with binomial distribution $B(n,p)$ is equal to the value $k$, where $k = 0, 1,\dots,n$. If we have the $(n\times m)$matrix and $N_j$,
$$f(x)= 1/2 \binom{3}{...
- 85
4
votes
4
answers
281
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How to combine some ordered pairs
I have a list of ordered pairs:
{{1, 1}, {1, 2}, {2, 4}, {1, 2}, {1, 2}, {2, 4}, {2, 4}, {2, 4}, {4, 4}}
If two pairs {x_1, y_1}...
1
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0
answers
48
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Formatting control points for BSplineFunction
I am trying to create an approximation to a level surface $F(u,v,w) = 0$ using BSplineFunction and control points sampled from the ContourPlot. I want to use these points to make a 2-variable ...
- 11
3
votes
2
answers
97
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Flatten bottom $n$ levels [closed]
The documentation for Flatten states:
Flatten[list,n] – flatten out the top $n$ levels in list
Does a function exist to ...
- 1,077
-1
votes
2
answers
109
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Combinations of two table
I would like to find all the possible combinations between TSet1 and TSet2 to create a table of 18 rows.
...
- 1,014
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0
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How can I make a list containing 5 rows and 10 columns from a list? [closed]
I have a list
list = RandomInteger[{10, 100}, 100]
I want to make a list containing 5 rows and 10 columns. I tried
...
- 1,265
3
votes
3
answers
240
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Inserting a 0 in Specific Symbols
I have a very large network with 1000's of edges. Below is a small sample. The N is my label for Node and the number that follows is a unique identifier. I want to make all the edges on either side of ...
- 1,817
1
vote
1
answer
56
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How can I compute the cross product of some sets of ordered pairs?
I have a list of sets of ordered pairs:
{{{1, 1}, {1, 2}, {2, 4}, {4, 8}}, {{1, 1}, {1, 2}}, {{1, 1}, {1, 2}}}
There are 4 ordered pairs in the first set, 2 ...
-2
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1
answer
86
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How can you transform the format of letters in a list，Character and parameter mutualization?
Q1:How to convert list1 into list2
list1={A, B, C, D, E, F}
...
- 4,868
2
votes
2
answers
97
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Condition on the data of table
If you have a table and want to separate some data into columns according to certain conditions:
Let's assume we have the following table:
...
- 1,014
5
votes
3
answers
427
views
How can I count frequency of a list faster?
I have a list
list = RandomInteger[{120, 180}, {20}]
I want to count from the list elements $a$ satisfying conditions: $120\leqslant a <130$, $130\leqslant a &...
- 4,317
3
votes
2
answers
66
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Using PutAppend to create data file for 2D plot
I need to append 2 real numbers x,y (a point coordinates) to the bottom of a file, so that these numbers form 2 columns, the x column and the y column. I need to plot the points later. Doing this:
<...
- 131
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votes
1
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64
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How to convert a $2 \times 2$ matrix with entries of $4 \times 4$ matrices into a regular $8 \times 8 $ matrix
I have tried to create the following matrix $$\begin{bmatrix} 0_{4} & \mathbb{I}_{4} \\ \mathbb{I}_{4} & 0_{4} \end{bmatrix}.$$
I have used the following code
...
- 673
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4
answers
145
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2
votes
1
answer
119
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Central element of matrix
Let we have $(2\cdot r+1) \times (2\cdot r+1)$ matrix mat.
Is there a better way to extract it's central element,
rather than ...
- 1,904
6
votes
3
answers
190
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Generate a table of elements whose number is equal to prime numbers
I have a list of words (strings) same as
...
- 659
1
vote
2
answers
71
views
Randomly replace some letters in words with hyphen
I have a list containing some related words
...
- 659
1
vote
1
answer
82
views
Find the feasible solutions of a minimal path set of vectors
Finding the feasible solutions for vectors representing minimum paths based on the mathematical basis:
First example
I need to create the constraints according to equations (1) and (2) above:
...
- 1,014
1
vote
1
answer
65
views
Max and Transpose in the Probability of a Union
If I have the code that gives the probability of the sum in general
...
- 1,014
1
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2
answers
132
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Probability of a union with probability function of vector
I want to calculate the probability of a discrete random variable.
...
- 1,014
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1
answer
55
views
Apply an equation based on two sets with different indexes
Apply an equation based on two sets with different indexes
Simple example
If I have the following elements in the form of two sets with different indexes:
$m=\{m_1,m_2,m_3,m_4,m_5\}=\{1,2,2,2,1\}$
$p=\...
- 1,014
7
votes
2
answers
286
views
How can I sort all levels except the innermost level?
How can I sort all levels except the innermost level? The number of levels is unknown. For example:
list = {{{d, c}, {b, a}}, {{4, 3}, {2, 1}}}
If we needed to ...
- 723
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2
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78
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Other methods extract the x-coordinates and y-coordinates from a list of multiple coordinate values and list them separately in two individual lists? [closed]
x={0.04,0.06,0.04,0.08,0.08,0.05,0.05,0.07,0.07,0.06}
y={0.25,0.4,0.22,0.54,0.51,0.34,0.36,0.46,0.42,0.4}
The two lists above represent sets of x-coordinates and y-...
- 4,868
2
votes
3
answers
304
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Filling the areas enclosed by two curves and calculate them
I know that there are plenty of posts on this, but I just cannot find the right one that solves my issue. The issue is that I have two datasets that I plot them using ...
- 1,309