4.39.1 Top new questions this week

4.39.1.1 How can I determine the type of a packed array?

https://mathematica.stackexchange.com/questions/157484/how-can-i-determine-the-type-of-a-packed-array

 
Packed arrays can be of type Integer, Real or Complex.  Knowing that an array arr is packed, how can I efficiently determine its type?
 

- asked by Szabolcs (15 votes), answered by Szabolcs (17 votes)

4.39.1.2 Deleting sublists from lists

https://mathematica.stackexchange.com/questions/157267/deleting-sublists-from-lists

 
I have a list consisting of symbols and integers.  I would like to delete the integers from the list only if a symbol precedes and follows each integer: 
 
testList={a,b,3,c,4,5,d,e,f,1,g,4} 
 
 
becomes: 
 
...
 

- asked by Suite401 (12 votes), answered by jjc385 (13 votes)

4.39.1.3 Summation bug in 11.2

https://mathematica.stackexchange.com/questions/157290/summation-bug-in-11-2

 
If I sum all the positive-numbered Fourier coefficients of $\cos(x)$, I get the correct answer. If I sum the negative-numbered ones, I get a wrong answer. Splitting the sum into two parts somehow  ...
 

- asked by level1807 (10 votes), answered by Michael E2 (14 votes)

4.39.1.4 Calculating the size of objects in the picture

https://mathematica.stackexchange.com/questions/157374/calculating-the-size-of-objects-in-the-picture

 
I'm new to Wolfram Mathematica. 
I have an initial image: 
 
 
 
My goal is to find a radius of the water drop, like so: 
 
 
 
With that in mind, I've changed the initial photo: 
 
resultImage =  ...
 

- asked by Elias (9 votes), answered by b3m2a1 (7 votes)

4.39.1.5 Overlapping graphic primitives

https://mathematica.stackexchange.com/questions/157489/overlapping-graphic-primitives

 
I am trying to make a figure in Mathematica using some graphic primitives: 
 
rod[l_, r_] :=   GraphicsGroup[{Opacity[.1], {Disk[{-l/2 + r, 0}, 
r, {\[Pi]/2 , 3 \[Pi]/2}]}, {Disk[{l/2 - r, 0}, 
r,  ...
 

- asked by Ruud3.1415 (7 votes), answered by kglr (3 votes)

4.39.1.6 How can I implement my own documentation search function?

https://mathematica.stackexchange.com/questions/157303/how-can-i-implement-my-own-documentation-search-function

 
The current documentation search doesn't allow for very sophisticate searching, can I write my own function to search through the docs?
 

- asked by b3m2a1 (7 votes), answered by b3m2a1 (8 votes)

4.39.1.7 Can I implement something like the old documentation help browser?

https://mathematica.stackexchange.com/questions/157317/can-i-implement-something-like-the-old-documentation-help-browser

 
Old versions of Mathematica had a help browser that was more click through and structured. How can I reimplement something like that for the new (since v6) docs?
 

- asked by b3m2a1 (6 votes), answered by b3m2a1 (10 votes)