Linked Questions
46 questions linked to/from Partitioning with varying partition size
3
votes
1
answer
492
views
Partition a list into sublists of unequal lengths according to a list of lengths [duplicate]
This is a conscious duplicate of On generalizing Partition[] (with offsets) to sublists of unequal length: it was seven years ago, and all answers are quite involved; maybe something easier has been ...
- 2,469
3
votes
0
answers
754
views
Splitting a list into sublists with different sizes [duplicate]
I have the list {7, 8, 9, 10, 11, 12, 13, 14} and would like to split it into a list of size 2, a list of size 3, and covert the remaining element into singleton ...
- 31
3
votes
1
answer
96
views
Non-Constant Partitioning of a List with Order Analysis [duplicate]
Let's say I have a set of numbers "r" whose sum equals 15, and I want to randomize all values up to and including that sum from and including 1 into a set called "a". So far I have this:
...
608
votes
19
answers
161k
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 ...
79
votes
9
answers
13k
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
...
- 261k
125
votes
3
answers
10k
views
What is a Mathematica packed array?
A simple sounding question with a few sub questions:
What is the difference between unpacked vs packed array?
Are packed arrays more space efficent, how much so?
Are packed arrays more time efficient ...
- 2,303
46
votes
10
answers
7k
views
Find zero crossing in a list
I'm looking for a function that finds the index of the zero-crossing points of a list. Before I go making my own subroutine to do this, I was wondering if anyone knows of any built-in Mathematica ...
- 1,011
22
votes
12
answers
1k
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Any built-in function to generate successive sublists from a list?
Given
lst = {a, b, c, d}
I'd like to generate
{{a}, {a, b}, {a, b, c}, {a, b, c, d}}
but using built-in functions only, ...
- 157k
44
votes
6
answers
4k
views
23
votes
10
answers
2k
views
UnFlatten an array into a ragged matrix
Trying to unflatten an array that was part of ragged array of sub matrices.
As input we have flattened array:
...
- 3,362
15
votes
6
answers
2k
views
Efficient conditional Mean[] on a large data set
Consider a list, AK6, that has 382 sublists of length varying from 2500 to 3000. Each "subsublist" is as such : ...
- 5,629
23
votes
6
answers
1k
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How to generate all possible orderless partitions of a list according to another list?
This question is hard to describe in plain text. So I will post an example and a working code (brute force) to illustrate.
For example I have a list: ...
- 7,946
13
votes
11
answers
796
views
Positions of elements in the initial flattened list in a split list
Say, we have a list:
m1 = {2, 2, 7, 0, 7, 7, 2, 2, 2}
It can be split easily:
...
- 5,017
16
votes
8
answers
3k
views
Populate an upper triangular matrix from a vector of elements
What is the best way to populate an upper triangular (or alternatively: lower triangular or symmetric) matrix from a vector of elements?
This example input:
...
- 239k
10
votes
6
answers
3k
views
How to efficiently input matrices in Mathematica (compared to what MATLAB offers)
Every time I want to manually input a matrix in Mathematica, it takes me a while since every new row has to be in a separate pair of curly braces.
For instance:
...
- 2,560