Linked Questions

10
votes
3answers
1k views

How to build a matrix from a set of vectors and other matrices using ArrayFlatten

I want to build a 6 by 3 matrix, from the following: one vector is 3 by 1, then a matrix, which is 3 by 2. These will go to the top 3 rows. Now the bottom 3 rows, I'll have 3 vectors each is 3 by 1. ...
9
votes
2answers
1k views

Understanding Transpose

It is very likely that it is my lack of math skills that is showing up here. However, I think Transpose is such an important function that I need to master it. So I ...
9
votes
3answers
924 views

Operations on elements of ragged lists

Suppose I have a list of lists with different lengths, sorted from longest to shortest ...
4
votes
2answers
4k views

Calculate mean and standard deviation from ImageHistogram

I am doing my PhD in Clinical Neuropsychology; I had someone helping me analyse images (.jpg pictures) in Mathematica, but it turns out this person made some really bad decisions, and well, now I have ...
10
votes
2answers
380 views

How to riffle matrices

I have four matrices ...
10
votes
1answer
393 views

Plotting how sunrise times change over the year

I created a somewhat lengthy Python code to show how the time of sunrise varies over a year, resulting in the following figure (daylight savings were disregarded): The dataset can be found here. The ...
2
votes
3answers
481 views

Applying the vec operator

How to apply the $\operatorname{vec}$ operator in Mathematica? For example, how can I transform a $2 \times 2$ matrix into a $1 \times 4$ matrix as follows? $$ \operatorname{vec}\left( \begin{...
2
votes
3answers
185 views

How to find all prime power factorizations of an integer

I want to put in $n$ and get the possible factorizations into prime powers. Let's say for 24 I want {{8,3}, {4,2,3}, {2,2,2,3}}. The algorithm for doing this on ...
3
votes
2answers
254 views

Inserting rows of one matrix into rows of another matrix sequentially

I have two matrices M1 and M2. Both have same number of columns but different number of rows. I want to make a new matrix M which should have 1st row form M1, second row form M2, third row form M1, ...
2
votes
2answers
421 views

How can I thread lists of different sizes?

What I need is the equivalent of Maple's zip(+, A, B, 0). Sure I can get it with: ...
5
votes
3answers
94 views

Adding the data of different tables

I have three tables of data say t1 = {{1, 2}, {2, 3}, {3, 4}}; t2 = {{1, 3}, {2, 3}, {3, 5}}; t3 = {{1, 3}, {2, 3}}; First I want to add ...
1
vote
2answers
132 views

Flatten a four dimensional array into a matrix

What is the simplest way to transform an array of the form ...
3
votes
2answers
199 views

How to convert multidimensional matrix into regular matrix?

I have this multidimensional matrix: {{{{a1, a2}, {a3, a4}}, {{b1, b2}, {b3, b4}}}, {{{c1, c2}, {c3, c4}}, {{d1, d2}, {d3, d4}}}} I would like to convert it into ...
2
votes
1answer
332 views

Flatten a list at some level

I wonder if is possible flatten a list at the last level without flattening at the first level, I think that isn't a good explanation so here is my code ...
1
vote
1answer
111 views

Combining the entries of two lists [closed]

I have two lists {a, b, c, d, e} and {1, 2, 3, 4, 5}. I want to creat a new list of tuples as follows ...

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