9.8.1 Top new questions this week

9.8.1.1 In a list, how to pick whatever is not f and its derivatives?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=280541

Suppose I have a list like: 
 list1 = {{f[x], Sin[x]}, {f'[x]}, {f''[x]}}; 
list2 = {{f[x]}, {Cos[x], f''[x]}}; 
 
I want to pick these lists and convert them to: 
... 
[list-manipulation] [replacement]
 

asked by Red Banana https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=603 Score of 10

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

9.8.1.2 How do I withdraw the rhs from a list of equations?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=280623

I have a list of equations that were solved for different values of another parameter and stored in a Table and has the form: 
 {a==0, a==1, a==2, a==3} 
 
and so on. I ... 
[list-manipulation] [replacement] [evaluation]
 

asked by qubiKat https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=80942 Score of 6

answered by Ulrich Neumann https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=53677 Score of 4

9.8.1.3 Fast pairwise difference

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=280457

I'm trying to construct a matrix $A_{ij}=X_i-Y_j$ where $X$ and $Y$ are vectors with thousands of real numbers. The fastest and closest thing I found is ... 
[list-manipulation] [matrix] [mathematical-optimization]
 

asked by Vsevolod A. https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=51665 Score of 6

answered by Henrik Schumacher https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=38178 Score of 6

9.8.1.4 How can I digitize the vector figure?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=280713

Consider the following figure in .pdf format. Its .png version is below: 
 
I would like to digitize it, i.e., e.g., extract the data for the brown curve $a\to KK\pi$. How can I do this, using the fact ... 
[plotting] [syntax] [digitization]
 

asked by John Taylor https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=41058 Score of 5

answered by Julien Kluge https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=34129 Score of 11

9.8.1.5 Can I exit a Map over a list of data pairs?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=280645

I've written a function, which I intended to  Map  over lists of some 8,000 element pairs. 
I created the "toy" code below to illustrate my problem. 
... 
[map]
 

asked by Jagra https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=571 Score of 5

answered by user1066 https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=106 Score of 6

9.8.1.6 How to keep lines on boundary or inside a region?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=280682

This post is related to one of my previous posts. My goal is to keep only the lines that fall on the boundary  (2, 8)  or inside the region ... 
[functions] [performance-tuning] [function-construction] [regions]
 

asked by hana https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=82512 Score of 5

answered by kirma https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=3056 Score of 6

9.8.1.7 DSolve solution for 1st order PDE involving complex number does not match initial condition

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=280590

Bug introduced in 11.3 or earlier, persisting through 13.2.1. 
 
[Mathematica 12.0.0.0, MacOS X x86 (64bit)] 
Trying to solve 
... 
[differential-equations] [bugs] [symbolic] [complex] [boundary-conditions]
 

asked by AlephBeth https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=19678 Score of 4