2.11 Thursday, October 1, 2020

2.11.1 Top new questions this week

What is a good way of perfoming operations on specified columns of a table with many columns

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=230854

If I have a table of data and I want to do a specific operation on say the third column, I usually do something like this:

asked by Q.P. https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=27119 11 votes

answered by kglr https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=125 8 votes

Quickest way to test whether array is constant

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=230971

At the moment I use Length[ DeleteDuplicates[ array ] ] == 1 to check whether an array is constant, but I’m not sure whether this is optimal. What would be the ...

asked by Gert https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=27889 11 votes

answered by Sjoerd Smit https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=43522 9 votes

Solving a rotating combination lock puzzle

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=230749

The following puzzle appears in The House of da Vinci II and I thought it might be interesting to tackle in Mathematica:

There are numbers marked on four rotating cylinders. These numbers must add up ...

asked by flinty https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=72682 9 votes

answered by C. E. https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=731 8 votes

Shortest way to make a checkerboard pattern

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=230988

I’m looking for the shortest (in terms of characters) code snippet to make an n-square checkerboard. Here’s my first try (comes in at 72 characters):

asked by M.R. https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=403 7 votes

answered by kglr https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=125 9 votes

Smoothing the Region?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=230725

There is a 2D Pi

I successed transformed it to 3D.

asked by partida https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=15961 7 votes

answered by xzczd https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=1871 9 votes

How to replace only the isolated variable x?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=230717

I want to replace the variable x in the result, not x in unrelated x[i]

asked by A little mouse on the pampas https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=42417 7 votes

answered by kglr https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=125 11 votes

Counting Elements in Multiple Lists

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=230864

How to build a table that counts how many times each element in mainlist occurs in lst1, lst2, lst3, lst4 and which lst1, lst2, lst3, lst4 contains that element. For example, in mainlist, element ...

asked by PRG https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=42700 6 votes

answered by kglr https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=125 7 votes

2.11.2 Greatest hits from previous weeks

What does # mean in Mathematica?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=19035

I asked Mathematica to compute the following

Solve[c (1-x)^2-x^(1/4) == 0, x] 
 
and it returned this: 
  x = Root[#1^8 c^4 - 8 #1^7 c^4 + 28 #1^6 c^4 - 56 #1^5 c^4 ...

asked by ronanymous https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=5730 37 votes

answered by Dr. belisarius https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=193 64 votes

Where can I find examples of good Mathematica programming practice?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=18

I consider myself a pretty good Mathematica programmer, but I’m always looking out for ways to either improve my way of doing things in Mathematica, or to see if there’s something nifty that I haven’t ...

asked by J. M.’s discontentment https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=50 550 votes

answered by faysou https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=66 484 votes

How do I identify the source of a "Tag times protected" error?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=11982

I have some code that looks like

Table[ 
    a = 1; 
    b = {2, 3} 
    c = i;, 
    {i, 2} 
] 
 
which gives an error: 
  Set::write: Tag Times in c {2,3} is Protected....

asked by dearN https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=204 28 votes

answered by Mr.Wizard https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=121 35 votes

How to create a new "person curve"?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=17704

Wolfram|Alpha has a whole collection of parametric curves that create images of famous people. To see them, enter WolframAlpha["person curve"] into a Mathematica ...

asked by Simon https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=34 83 votes

answered by Vitaliy Kaurov https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=13 45 votes

Mathematica 10.0.x freezes in Initializing kernels

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=92931

Bug caused by paclet update and fixed by paclet update.

I updated to Windows 10 and have been running Mathematica fine on it for over a month. For some reason, it has just stopped working. I don’t ...

asked by mitcheljh https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=6783 80 votes

answered by ilian https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=145 101 votes

Extract real part of a complex expression better than Re does

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=3306

I have a complex expression with real positive variables only.

Mathematica Input Style:

asked by max https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=796 33 votes

answered by nixeagle https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=814 52 votes

Calculate the 2D Fourier transform of an Image

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=29203

I am new to Mathematica, and using version 8.0.

I would like to calculate the 2D Fourier Transform of an Image with Mathematica and plot the magnitude and phase ...

asked by user8727 https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=8727 15 votes

answered by Nasser https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=70 32 votes

2.11.3 Can you answer these questions?

Simplify Equation with variable unequal to zero

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=230846

How can I simplify the following equation with Mathematica assuming z!=0? I have the following code:

asked by Franz Ferdinand https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=74882 1 vote

finding primes using chebyshev bias

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=230943

Using the problem from my previous question link. For each n, that is n= \(10^3\) to \(10^6\) with a ten-fold increase, how do I use Chebyshev Bias to display the number of primes (which are in the ...

asked by complab56 https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=74866 1 vote

Why does NDSolve not give consistent results?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=230784

This is my code:

asked by S.J.E. Huisman https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=74858 1 vote