3.5.1 Top new questions this week

3.5.1.1 ++ is dangerous for C programmers

http://mathematica.stackexchange.com/questions/107619/is-dangerous-for-c-programmers

 
I noticed this fact, that may be misleading for programmers used to C language. 
 
In Mathematica, if you have a function f[] and an array v, and you write 
 
v[[ f[] ]]++ 
 
 
the function f is called  ...
 

- asked by Giovanni Resta (30 votes), answered by Mr.Wizard (23 votes)

3.5.1.2 Apply multiple functions to same list

http://mathematica.stackexchange.com/questions/107721/apply-multiple-functions-to-same-list

 
I'd like to get the Min, Max, Median, Mean, etc. for the same list.  For now I'm doing the following: 
 
y = {1, 2, 3, 4, 5, 6, 7}; 
Map[{Max[#] , Min[#] , Median[#], Mean[#]} &, y, {0}] 
 
 
It seems  ...
 

- asked by Mitchell Kaplan (15 votes), answered by Bob Hanlon (18 votes)

3.5.1.3 How do I delete all items that occur more than once?

http://mathematica.stackexchange.com/questions/107483/how-do-i-delete-all-items-that-occur-more-than-once

 
DeleteDuplicates works fine but leaves a single copy of the duplicated item. I need to remove all items that occur more than once i.e. {{1,2},{1,2},{3,4}} -> {3,4}. There must be a one-liner.
 

- asked by Boris (12 votes), answered by Leonid Shifrin (16 votes)

3.5.1.4 Puzzle with Mathematica

http://mathematica.stackexchange.com/questions/107859/puzzle-with-mathematica

 
 
 
Hello everyone, 
This is a puzzle I got from someone via social media. Basically, we need to fill up the boxes with the numbers 1-9 (no repetitions) that fit the multiplication and addition  ...
 

- asked by iFikr (11 votes), answered by unlikely (13 votes)

3.5.1.5 Finite Element Method and ElementMeshInterpolation issue in v10.3

http://mathematica.stackexchange.com/questions/107668/finite-element-method-and-elementmeshinterpolation-issue-in-v10-3

 
I recently installed Mathematica v10.3 and checked a project I was working on few months ago under Mathematica v10.1. 
 
In this project I solve a PDE with NDSolve and Finite Element Method over a 2D  ...
 

- asked by unlikely (10 votes), answered by Jason B (8 votes)

3.5.1.6 Efficient way to make subsets of list with placeholders

http://mathematica.stackexchange.com/questions/107517/efficient-way-to-make-subsets-of-list-with-placeholders

 
I have an arbitrary list of unique elements: 
 
lst = {a, b, c, d} 
 
 
Documentation allows finding subsets with same number of elements, say 2: 
 
Subsets[lst, {2}] 
(* {{a, b}, {a, c}, {a, d}, {b, c}, {b,  ...
 

- asked by garej (10 votes), answered by Dr. belisarius (10 votes)

3.5.1.7 Double Sum Involving Condition

http://mathematica.stackexchange.com/questions/107652/double-sum-involving-condition

 
I would like to compute the dimensions of some small free nilpotent Lie algebras. However, I am totally new to this and I could not figure out how to write the double sum which gives the dimension of  ...
 

- asked by Can Hatipoglu (9 votes), answered by J. M. (13 votes)