6.5.1 Top new questions this week

6.5.1.1 `Count` for `SparseArray`
6.5.1.2 What is the best and most efficient way to curry?
6.5.1.3 Mathematica and Excel
6.5.1.4 Local variables in sums and tables - best practices?
6.5.1.5 How can I make Mathematica solve this set of four equations?
6.5.1.6 obtain properly formatted code from autogenerated package
6.5.1.7 Why is StreamPlot plotting direction like this?
6.5.1.1 `Count` for `SparseArray`

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=221160

Why does Count not work with SparseArrays, and is there any function I can use to replace it? 
 
What would be an efficient workaround? 
 
Example: 
 
a=ConstantArray[0,{10},SparseArray]; 
Count[a,0] (*  ... 
[sparse-arrays] [counting]
 
asked by Daniel https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=19534 9 votes
answered by thorimur https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=63584 8 votes
6.5.1.2 What is the best and most efficient way to curry?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=220972

Suppose I have a function with a signature like g[expr, _?(f), {1}, Heads -> False] and I want to access it as an operator by giving the first argument last. I see there are various ways of doing  ... 
[performance-tuning] [function-construction] [currying]
 
asked by user13892 https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=13892 9 votes
6.5.1.3 Mathematica and Excel

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=221155

I have a number of large data sets in Excel and .dat from OMEdit Modelica that then need to import some or all of it to Mathematica for manipulation and plotting.  Importing the data is easy enough  ... 
[excel]
 
asked by Chris B https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=58764 8 votes
answered by kglr https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=125 10 votes
6.5.1.4 Local variables in sums and tables - best practices?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=221079

Stumbled on Local variables when defining function in Mathematica in math.SE and decided to ask it here. Apologies if it is a duplicate - the only really relevant question with a detailed answer I  ... 
[table] [summation] [scoping] [variable-definitions]
 
asked by   https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=35000 8 votes
answered by WReach https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=142 5 votes
6.5.1.5 How can I make Mathematica solve this set of four equations?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=221082

I use Mathematica version 12.1 on Windows 10. 
 
I have four equations in four unknowns. 
 
Is there a trick to make Mathematica solve these? 
 
I tried Solve and NSolve and it is not able to do it.  ... 
[equation-solving] [matrix]
 
asked by Nasser https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=70 8 votes
answered by J. M.'s technical difficultieshttps://mathematica.stackexchange.com/landing/r/digest?cta=user&id=50 7 votes
6.5.1.6 obtain properly formatted code from autogenerated package

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=220842

Overview: 
I have written a few mathematica packages, always using the method of writing my code in a mathematica notebook and letting mathematica autogenerate the .m package file. Currently I do not  ... 
[notebooks] [packages] [formatting]
 
asked by Wizard https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=5033 8 votes
answered by Szabolcs https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=12 6 votes
6.5.1.7 Why is StreamPlot plotting direction like this?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=221255

I am doing a StreamPlot and something seems wrong with the output. 
 
StreamPlot[{0, -(y - x)^3}, {x, -3, 3}, {y, -3, 3}] 
 
 
The plot is attached and I highlighted the issue in red 
 
 
 
Shouldn't the  ... 
[plotting]
 
asked by Moo https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=36141 7 votes
answered by user2432923 https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=61643 5 votes