2.3.1 Top new questions this week

2.3.1.1 Faster position list construction from a "take instructions" list

http://mathematica.stackexchange.com/questions/77542/faster-position-list-construction-from-a-take-instructions-list

 
Take some list, e.g., {1,2,3,4,5}, and a "take instructions" list, say 
{1,1,2,1,1}. 
 
The latter is read as "take the first element from the list, drop it 
from the list, take the first element of the  ...
 

- asked by rasher (16 votes), answered by 2012rcampion (9 votes)

2.3.1.2 Capturing Data from an Android Phone

http://mathematica.stackexchange.com/questions/77514/capturing-data-from-an-android-phone

 
Is there a way to capture Data from an android phone to be later 
analyzed in Mathematica?
 

- asked by Zviovich (10 votes), answered by Zviovich (10 votes)

2.3.1.3 Match opening and closing parentheses?

http://mathematica.stackexchange.com/questions/77779/match-opening-and-closing-parentheses

 
Suppose I have a List of the form: 
 
lst={"(", "(", "(", ")", "(", ")", ")", ")"} 
 
 
By running Position[lst, "("] and Position[lst, ")"], I can get the 
positions of the opening and closing parentheses  ...
 

- asked by becko (8 votes), answered by Simon Woods (12 votes)

2.3.1.4 Segmenting Sections of Lines in an Image

http://mathematica.stackexchange.com/questions/77972/segmenting-sections-of-lines-in-an-image

 
I have taken several gps readings while driving around town. 
 
gpsPositions=GeoPosition[{{33.657, -84.5197}, {33.6687, -84.4977}, 
{33.692, -84.4907}, {33.7057, -84.4287}, {33.7431, -84.4027},  ...
 

- asked by Zviovich (7 votes), answered by nikie (8 votes)

2.3.1.5 Flatten nested lists

http://mathematica.stackexchange.com/questions/78030/flatten-nested-lists

 
I have a list as follows 
 
lis= {a, {{{b}, {c,d,e}}, {{f}, {g,h,i}}}} 
 
 
which I would like to flatten to 
 
flattenLis={a,{b,c,d,e},{f,g,h,i}} 
 
 
Does anyone have a hint. All my flatten attempts did not  ...
 

- asked by Phadreus (7 votes), answered by Kuba (7 votes)

2.3.1.6 How to make a binary function associative? (Or define an n-ary function?)

http://mathematica.stackexchange.com/questions/77913/how-to-make-a-binary-function-associative-or-define-an-n-ary-function

 
Suppose I have a simple function that I assign to an operator 
 
f[a_, b_] := a + b 
CirclePlus = f 
 
 
Then I want to write 
 
1 (+) 2 (+) 3 
 
 
But it doesn't work, because it's trying to evaluate f[1,2,3]. 
 
...
 

- asked by Noon Silk (7 votes), answered by halirutan (9 votes)

2.3.1.7 Strange answer from StringReplace

http://mathematica.stackexchange.com/questions/77771/strange-answer-from-stringreplace

 
I have a list of strings and I would check if there is an empty string 
element, that's "", because I need to replace it with a "0". I try the 
following 
 
StringReplace[{"90", "", "20"}, "" -> "0"] 
 
 
...
 

- asked by bobknight (7 votes), answered by Sjoerd C. de Vries (8 votes)