4.24 Tuesday, July 11, 2017

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Top new questions this week: 
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[Replace elements that do not match a pattern] https://mathematica.stackexchange.com/questions/149736/replace-elements-that-do-not-match-a-pattern

I have the following matrix

mat={{0,a,b},{c,0,d},{0,0,e}}

I would like to replace the zero elements of it with 1 and the remaining with zero. The first step would be

mat/.{0->1}

However I ...

- asked by Galuoises (12 votes), answered by eldo (7 votes)

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[Image segmentation by pixel value] https://mathematica.stackexchange.com/questions/149966/image-segmentation-by-pixel-value

I’m looking for a way to segment a grayscale image (or a 2D array) by its pixel values. We look at two neighboring pixels, if their values are close within a certain threshold, then we say they are ...

- asked by xslittlegrass (11 votes), answered by nikie (11 votes)

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[Can trees be made into graphs?] https://mathematica.stackexchange.com/questions/151155/can-trees-be-made-into-graphs

When one has the output of a function like TreeForm, for instance:

Can this be turned into a Graph object? I would like to be able to apply functions like VertexList, VertexDegree, AdjacencyList, ...

- asked by M. Brandt (8 votes), answered by C. E. (5 votes)

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[Layout tips to keep UI responsive] https://mathematica.stackexchange.com/questions/149835/layout-tips-to-keep-ui-responsive

Bug introduced in V10.4 or earlier and persisting through V11.1.1

  CASE:3914402 
 
 
Here is an example of a problem I have. Gutted version of something much bigger: 
 
handler2 =  Framed[#,     ...

- asked by Kuba (8 votes), answered by Kuba (1 vote)

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[How to use LaTeXin Mathematica text] https://mathematica.stackexchange.com/questions/151102/how-to-use-latex-in-mathematica-text

I would like to formulate a question in a notebook for my students using LaTeX(or MathML) to typeset functions and matrices. I specifically want a language other than Mathematica as students ...

- asked by user49947 (7 votes), answered by Nasser (6 votes)

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[getting zero for special positions in a matrix] https://mathematica.stackexchange.com/questions/149767/getting-zero-for-special-positions-in-a-matrix

There are a list

list={{1, 2, 3, 2, 3}, {3, 1, 1, 2, 3}, {3, 2, 1, 3, 2}, {1, 2, 1, 1, 1}}; 
 
 
I wish to have all elements be zero except the first 
and the fourth in each row: desired: 
 
list={{1, 0,  ...

- asked by Irreversible (7 votes), answered by tomd (7 votes)

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[To Work with Barchart or DiscretePlot?] https://mathematica.stackexchange.com/questions/149960/to-work-with-barchart-or-discreteplot

I would like to create a graph similar to this below using some slightly dotted bar style like the one shown in the figure ...

And I’m trying to open a space between bars 6 and 8, but I’m failing.

...

- asked by LCarvalho (7 votes), answered by kglr (6 votes)

================================== Greatest hits from previous weeks: ==================================

[How to manipulate 2D plots?] https://mathematica.stackexchange.com/questions/7142/how-to-manipulate-2d-plots

When it comes to visual analysis, large datasets or data with intricate internal details often makes plotting in 2D useless, as the outcome is either just a fraction of the full dataset, or no details ...

- asked by István Zachar (117 votes), answered by István Zachar (134 votes)

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[Learn Mathematica (Wolfram) Language in one day] https://mathematica.stackexchange.com/questions/138366/learn-mathematica-wolfram-language-in-one-day

Currently I am trying to learn Python. Searching for relevant material I came across

X in Y minutes

and books with titles such as Learn Python in one day, in 24 hours, etc.

Similar material exists ...

- asked by dimitris (25 votes), answered by masterxilo (9 votes)

================================== Can you answer these? ==================================

[Sorting a list of rules] https://mathematica.stackexchange.com/questions/149862/sorting-a-list-of-rules

When we give several definitions for a function f, the DownValues of f are automatically sorted with respect to the domain defined by the pattern:

f[x_]:=2; 
f[x_?Positive] := 3; 
f[1]=4; 
 ...

- asked by Fred Simons (3 votes)

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[Plotting orbits of trajectories of bodies sharing the earth’s orbit in coordinates centered at the barycenter of the solar system] https://mathematica.stackexchange.com/questions/151069/plotting-orbits-of-trajectories-of-bodies-sharing-the-earths-orbit-in-coordinat

I am attempting to try and plot the trajectories of a trio of satellites that are orbiting with the earth-moon system around the solar system’s barycenter. Originally, I had the satellites in orbit ...

- asked by SSoltero (1 vote)

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[Mathematica not releasing RAM] https://mathematica.stackexchange.com/questions/151127/mathematica-not-releasing-ram

The following code is supposed to sequentially read data from a large CSV file and put it row by row into an SQL server. Although I thought RAM consumption should be constant the system keeps asking ...

- asked by user13892 (2 votes)