3.2.1 Top new questions this week

3.2.1.1 How can I access NASA images and APIs?

https://mathematica.stackexchange.com/questions/163638/how-can-i-access-nasa-images-and-apis

I ♥ NASA. You ♥ NASA. We all ♥ NASA.

So how can I use the images and things they expose in their APIs in Mathematica?

- asked by b3m2a1 (23 votes), answered by b3m2a1 (29 votes)

3.2.1.2 Access last variable in a pure function?

https://mathematica.stackexchange.com/questions/163469/access-last-variable-in-a-pure-function

# is the first argument of a pure function, #n the nth, ## are all 
variables and ##n all beginning with the nth variable.

Now, I would like to access the last argument. In a list, this would be ...

- asked by riddleculous (13 votes), answered by Henrik Schumacher (14 votes)

3.2.1.3 Ordered RandomSample

https://mathematica.stackexchange.com/questions/163498/ordered-randomsample

This feels like a basic question yet I failed to find an answer.

  (*arbitrary list of unique elements, does not need to be sorted*) 
list = CharacterRange["a", "h"]; 
n = 5; 
 
RandomSample[ list, n]

asked by Kuba (11 votes), answered by Coolwater (13 votes)

3.2.1.4 Possible bug in Refresh[x, None] on the very first x = val

https://mathematica.stackexchange.com/questions/163559/possible-bug-in-refreshx-none-on-the-very-first-x-val

Bug introduced in 8 or earlier and persisting through 11.2.0

 
>From Refresh docs: 
 
 
  Refresh[expr,None] specifies that the value of expr 
should never automatically be refreshed. 
 
 
ClearAll[z] 
 ...

asked by Kuba (8 votes)

3.2.1.5 How to launch a separate Java VM on each sub-Kernel?

https://mathematica.stackexchange.com/questions/163387/how-to-launch-a-separate-java-vm-on-each-sub-kernel

I have some code that process very large flat files in to separate HSQL(Standalone) databases using ParallelSubmit and JDBC for each file using the strategy in this post (19542). Lately I keep ...

asked by Edmund (8 votes), answered by Edmund (5 votes)

3.2.1.6 Three differential equations

https://mathematica.stackexchange.com/questions/163566/three-differential-equations

I have the next figure with inflow and outflow rates:

And I need to calculate the time for which the pollution will be 50% from the initial value. Assuming that all lakes have the same pollution ...

asked by Darius Ionut (8 votes), answered by Henrik Schumacher (8 votes)

3.2.1.7 How can I create an enumeration variable by groups?

https://mathematica.stackexchange.com/questions/163764/how-can-i-create-an-enumeration-variable-by-groups

I copied the title and concept for this question from here. I have

data = {{"ID", "Value"}, {1, 48}, {1, 45}, {1, 52}, {1, 43}, {1, 
    41}, {2, 50}, {2, 42}, {2, 51}, {2, 52}, {bb, 52}, {bb, 54},  ...

asked by ramesh (7 votes), answered by kglr (8 votes)