Linked Questions
14 questions linked to/from Looking for a way to insert multiple elements into multiple positions simultaneously in a list
604
votes
19
answers
158k
views
Where can I find examples of good Mathematica programming practice?
I consider myself a pretty good Mathematica programmer, but I'm always looking out for ways to either improve my way of doing things in Mathematica, or to see if there's something nifty that I haven't ...
78
votes
9
answers
12k
views
How to efficiently find positions of duplicates?
Is there an efficient way to find the positions of the duplicates in a list?
I would like the positions grouped according to duplicated elements. For instance, given
...
- 245k
14
votes
8
answers
2k
views
Given an ordered set S, find the points in S corresponding to another list
Given a sorted list of numbers $S$, I want to create a function that accepts a list of numbers $L$ and for each number $l \in L$ it returns the index of the largest number $s \in S$ such that $s<l$....
- 132k
10
votes
7
answers
359
views
How to insert elements at different locations of a given list
Say a list is given as
list = {a, b, c, d, r, m, n};
Suppose I want to insert 2 and 3 at position 3 and 7, respectively.
...
- 704
13
votes
5
answers
290
views
Inserting some zeros in a list by a rule of positions
I have a list:
mainlist={0.23, 0.34, 0.8, 0.0, -0.2, 0.4, -0.1};
I have to extend the above list to another one finalresult ...
- 1,533
11
votes
4
answers
2k
views
How to insert / merge a list into another list?
Background: I am working on a 2D geometry algorithm where I need to insert a list of 2D points into another list of 2D points. Somewhat to my surprise I found no Mathematica function capable of doing ...
- 9,687
11
votes
5
answers
2k
views
Relational joining of tables
A common thing to want to do with data is to combine it (at least I thought this was a common thing). In SQL there is the idea of table joins "select id,v1,v2 from A,B where A.id=B.id" kind of thing. ...
user9444
5
votes
6
answers
276
views
Pairing headers with each subsequent entry in a flattened list
I have a list containing headers of the form a-*; each followed by a variable number of entries:
...
- 5,025
8
votes
4
answers
1k
views
Efficient method for Inserting arrays into arrays
This is strongly related to the following Questions:
Looking for a way to insert multiple elements into multiple positions simultaneously in a list
Building matrices by attaching vectors (columns) ...
- 1,867
3
votes
5
answers
1k
views
Randomly selecting and reinserting a subset of elements in a list
This question is similar to my other question: How do I randomly select 'k' positions in a list and shuffle their respective elements without effecting the other elements?
Imagine first a ...
- 115
1
vote
3
answers
347
views
professionalize/optimize my code that calls a function
I have the following construction, which defines a function that I subsequently call in a loop multiple times. I use this very often, but I have never looked into if there is a more professional way ...
- 1,283
3
votes
3
answers
413
views
How to double elements of a list given by their positions
Given that I have a list $\{P_0,P_1,P_2,\cdots,P_7\}$, where, $P_i$ is a real number or a list like {x,y}/{x,y,z}. Now I would like to double some elements ...
- 655
1
vote
2
answers
355
views
Insert at specific resulting positions?
I have an initial list:
list0 = {1,2,3,4,5};
and I want to insert {a,x} at specific positions ...
- 11.5k
1
vote
1
answer
58
views
How to avoid multiple copies of a list when mapping a pure function to it?
Given this code:
mylist = Tuples[{a, e}, 2];
Insert[mylist, 1, {#, 3}] & /@ Range[2]
The output is this:
{{{a, a, 1}, {a, e}, {e, a}, {e, e}}, {{a, a}, {a,...
- 2,341