11.30.1 Top new questions this week

11.30.1.1 Counting steps on a staircase
11.30.1.2 Extracting several sets from a list efficiently
11.30.1.3 Rotating 3D graphics with efficiency of front-end
11.30.1.4 Prevent error message on accidental mouse drag on dynamic 3d graphics
11.30.1.5 Why doesn't Dynamic[1+x] lead to Set::write warning?
11.30.1.6 How to find "minimal polynomial" of a rational number?
11.30.1.7 How can I specify the first tabular column as date at import?
11.30.1.1 Counting steps on a staircase

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=315249

This is a recreational question. At my workplace within the same stairwell there are different steps numbers per floor on certain floors. 
I have tried to automate counting the steps by binarising the ... 
[image-processing]
 
asked by ubpdqn https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=1997 Score of 8
answered by ubpdqn https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=1997 Score of 2
11.30.1.2 Extracting several sets from a list efficiently

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=315203

Suppose we have a list and a list of lists of positions to extract from the list. 
... 
[list-manipulation] [performance-tuning]
 
asked by Anton https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=81381 Score of 6
answered by Anton https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=81381 Score of 4
11.30.1.3 Rotating 3D graphics with efficiency of front-end

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=315233

Evaluate the following code and use your mouse to rotate the graphics - it is fluent without any delay. 
... 
[performance-tuning] [graphics3d] [manipulate] [front-end] [rotation]
 
asked by azerbajdzan https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=53172 Score of 5
answered by Domen https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=75628 Score of 7
11.30.1.4 Prevent error message on accidental mouse drag on dynamic 3d graphics

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=315245

Here is an example how to use  Dynamic  inside  Manipulate  for smooth rotation. But it does not work for the following code. 
... 
[graphics3d] [manipulate] [front-end] [dynamic]
 
asked by azerbajdzan https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=53172 Score of 5
answered by xzczd https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=1871 Score of 5
11.30.1.5 Why doesn't Dynamic[1+x] lead to Set::write warning?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=315248

According to the document of  Dynamic : 
 
If the displayed form of  Dynamic[expr]  is interactively changed or edited, an assignment <... 
[front-end] [dynamic] [documentation]
 
asked by xzczd https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=1871 Score of 5
answered by Kuba https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=5478 Score of 6
11.30.1.6 How to find "minimal polynomial" of a rational number?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=315212

I suspect that  1.0982  is (close to) the root of a low degree ( 2  or  4 ) polynomial with small ... 
[polynomials] [approximation]
 
asked by pdmclean https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=9154 Score of 5
answered by mikado https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=36788 Score of 7
11.30.1.7 How can I specify the first tabular column as date at import?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=315231

I am importing an external CSV file using 
 Import["myfname.csv", "Tabular", HeaderLines -> 1] 
 
The first row is a header row, and the first ... 
[tabular] [importing-data]
 
asked by Alan https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=19530 Score of 5