Questions tagged [sorting]
Questions on the sorting/ordering functions of Mathematica (Sort, SortBy, Ordering, etc.).
2
votes
2answers
97 views
Inserting an integer into a sorted list
I'm wondering if inserting an integer into a sorted list (in a way that the list remains sorted) can be performed in Mathematica in some fancy way in $\log(N)$ time?..
The question was asked here, ...
3
votes
2answers
303 views
What is the Alphabetical Inequality Test?
Mathematica can sort {"b","d","a","c"} into {"a","b","c","d"} with a simple application of ...
5
votes
2answers
195 views
How can I order this list on mathematica?
This is my list
Matrix = {{1, -2, 3, -4}, {{a, b}, {f, e}, {a, b}, {f, e}}}
I want to order the columns in ascending order depending on the values on the first ...
12
votes
1answer
206 views
OrderedQ with string arguments
I don't find these results consistent:
OrderedQ[{"a", "A"}]
True
OrderedQ[{"a2", "A1"}]
False
Is there any ...
0
votes
1answer
35 views
How to assume lexicographical ordering
Suppose I have functions which depends on the symbols $c[I]$, where $I$ is some subset of $\{1,2,...,n\}$.
For example, $$f = c[1] + c[1,2,3] + c[1,2],$$ $$g = c[2] + c[2,1],$$
Code:
...
15
votes
6answers
776 views
Better way to sort course grades
I use the following code to create a histogram of grades. Grades are provided as a List of strings such as "A-", "D+", "E" (don't ask), etc. The +/- substitution hack is necessary to sort the grades ...
1
vote
0answers
37 views
In what order does Combinatorica's SetPartitions function list the partitions of a set?
For example,
Needs["Combinatorica`"]
n = 4;
partitions = SetPartitions[Range[n]];
Table[Print[partitions[[i]]], {i, 1, BellB[n]}]
generates
...
2
votes
2answers
52 views
Nested sorting of lists
I have the following list representing a custom set of cards:
Each card is represented by a list of two elements, like this: {heart,9}
Using the code:
...
1
vote
3answers
54 views
Sorting out list elements that are nonlinear in a certain function
I have the following (long) list (exemplary I will show you only a few elements of it):
...
11
votes
1answer
113 views
stable sort for association?
Should I be able to use the "list of functions" approach to getting a stable sort of an association? In 11.1 I see,
...
1
vote
1answer
40 views
Import image files in the order of the file name number [duplicate]
I would like to import images which are frames from a video, they are numbered, so importing them in the correct order should not be a problem...
However, when I import them, by writing:
...
1
vote
1answer
56 views
How to order a sum in ascending order of the powers? [closed]
Consider the sum
x^1+x^3+x^2+x^4
I want to order this sum in such the I have the powers in ascending order
x^1+x^2+x^3+x^4
...
10
votes
1answer
161 views
Quick QuickSort implementation
I am playing with julialang and loving it, but at the same time noticed that they have a benchmark comparison with Mathematica. I have already submited a better version of ...
3
votes
2answers
41 views
5
votes
1answer
54 views
How to sort the data by several columns (some ascending and some descending)?
I have sorted the data firstly by the 3rd column and then by the 2nd column as below:-
a = RandomInteger[20, {30, 3}]
SortBy[a, {#[[3]], #[[2]]} &]
As you ...
0
votes
0answers
12 views
Maintain written order in expression (lexicographic sorting rules) [duplicate]
Is there any way I can get output to follow the exact order that I wrote it?
For instance (simple example)
x = z + a - b + c^2
comes out as
...
4
votes
1answer
56 views
Sort images by difference
I can use ImageDistance to get the Euclidean distance between two images. But, I have list of (~100) images, and I want to sort them such that the average ...
1
vote
1answer
71 views
Why do I need a second Function in SortBy for Association?
I cannot understand why I need a second pure function when trying to sort Association by Key. Here is an example
...
6
votes
6answers
339 views
0
votes
1answer
39 views
Delete duplicates and sort a list of sets separately? [closed]
I have a set where it has three subsets. I want to have each element of each subsets appears only once, sorted, but the order of subsets does not change. For example: I want to get from
$$
\{\{5,2,2,3\...
0
votes
0answers
37 views
SortBy not working in a delayed output
I have a table of large number of elements, each with three elements, say
A = {{a, b, c}, {e, f, g}...}.
I am using the function ...
0
votes
2answers
46 views
Sorting a table wrt to last two elements
I have a table-1 having 36 elements, each having the form {A, m, n}, where m & n are the indices (1-6).
There is another table-2 having 36 elements {m, n} in a particular order (like {{4, 3}, {2, ...
0
votes
0answers
26 views
How can I get a specific ordering in the matrix and the results of a system linear equations?
I have a linear system of 22 equations and variables. When I create the matrix form it sorts the coefficients on the first row (X1, X10, X11, ...) This ordering repeats for all columns and all the ...
8
votes
1answer
154 views
How to find the position in original list ranked first by SortBy
SortBy is a wonder and convenient way to sort a list using a list of functions with which ties can be broken.
...
1
vote
1answer
36 views
Changing the display ordering of orderless functions?
If I write
x = -(1 - 2 G M/r) \[DoubleStruckD]t^2 + (1 -
2 G M/r)^-1 \[DoubleStruckD]r^2 + r^2 \[DoubleStruckD]θ^2 +
r^2 Sin[θ]^2 \[DoubleStruckD]ϕ^2;
x
I see
...
1
vote
1answer
55 views
Feyncalc remove higher-order TensorFunction terms from expression
I am looking for a way to reduce the following expression:
...
0
votes
2answers
80 views
5
votes
2answers
152 views
How to replace columns of a matrix with an unsorted ordered list.
I have a matrix that I would like to replace the values of each column with where they are in an ordered list of values from least to greatest. For example, if I have
...
2
votes
2answers
179 views
How to sort ordered pairs by one coordinate with the other serving as tie-breaker [closed]
I have a collection of $N$ ordered pairs,
$$\{\{x_{1},y_{1}\},\cdots,\{x_{N},y_{N}\}\}$$
These ordered pairs can have at most one entry in common, i.e., if $x_{i}=x_{j} \left(y_{i}=y_{j}\right)$ ...
0
votes
0answers
54 views
How to sort eigenvalues by eigenvector in a table [duplicate]
I'm trying to look at the evolution of the eigenvalues of a matrix as a function of magnetic field. My problem is that the eigenvectors are not ordered according to their eigenvector. I can sort these ...
2
votes
3answers
50 views
How can I generate a list of function calls in the sort order of values of the calls?
My problem is that I have a defined function, say, foo, and I am using the built in Sort function to order a sequence of calls
<...
2
votes
1answer
56 views
How to sort string codes by their alpha and numeric tokens?
I have a large list of codes of the following form:
codes = {"Fee.C21HJ.S4", "Fee.TOxC12.S1", "Fee.TOxC9.2 BB", "Fee.ROxC9.4", "Lag.C39"};
I would like to sort ...
2
votes
1answer
319 views
What is “standard” or “canonical” order? [duplicate]
When trying to sort a list of fractions and quadratic numbers I'm trying to work out why sort orders the quadratics after the fractions. It seems to use the function "OrderedQ" and "standard order" or ...
0
votes
1answer
30 views
Sort solutions obtained with the resolution of a system
After the resolution of a system of 4 equations, i obtained these solutions :
...
2
votes
2answers
80 views
Difference between (#1[[2]] < #2[[2]]&) and (#1[[2]] & < #2[[2]] &) [closed]
For example, if I have a list {{a, 2}, {c, 1}, {d, 3}} and I want to sort it w.r.t. the numbers:
...
8
votes
2answers
515 views
How to SortBy Last and in Reverse order?
I am looking at the two functions SortBy and ReverseSort.
...
1
vote
1answer
35 views
Reordering matrix variables with subscripts
I want to calculate a matrix product that preserves the ordering of variables as x then a then ...
0
votes
0answers
38 views
Sort the terms of expression by the given order?
Let's assume I have the following expression :
D[K[x,y],{x,1}] + D[J[x,y],{x,2},{y,2}] + D[U[x,y],{x,2},{y,1}].
Can we sort it by the order corresponding to ...
0
votes
0answers
39 views
Evaluating multiple processes and sort the results
I would like to evaluate the code below and sort the two parameters {f2, M}. Say that i runs from 1 to 10
...
6
votes
2answers
128 views
Creating lists within lists by sorting
I've been working with lists and am stuck on creating lists within a list based on the first element within that list.
So for instance, if I have the list:
...
1
vote
1answer
58 views
MaximalBy in case of missing column entries
I have a large dataset, resulting from a JoinAcross operation, which looks similar like this one (only more complicated)
...
3
votes
1answer
98 views
6
votes
2answers
88 views
Sorting elements in a table with respect to another table
I have two tables, each having three rows (R1, R2 & R3). The elements of R2 & R3 are same in two tables but in different orders. The elements in row R1 are different in two tables. I want to ...
0
votes
1answer
90 views
2
votes
0answers
34 views
Sort Voronoi cells by their generator points [duplicate]
When I create a Voronoi diagram from a set of generator points and then recover the cells through MeshPrimitives, the order of the cells does not match the order of ...
8
votes
0answers
93 views
What do the Internal`Compare* functions do?
As part of looking at this question I dug into Names["Internal`*Compare*"] and ended up with:
...
3
votes
2answers
142 views
Output all steps of Sort [duplicate]
Is there a way you output each partial result of the Sort function? i.e.
Sort[{2,3,1}]
{2,1,3}
{1,2,3}
-1
votes
1answer
83 views
Extract part of list
I have the following list:
{{{1, 0, 0}, {0.5, 1}}, {{2, 0, 0}, {0.5, 1}}, {{2, 0, 0}, {1, 1}}}
I would like to take the first part if the second part get a ...
4
votes
4answers
510 views
4
votes
1answer
123 views
Sorting a list of rules
When we give several definitions for a function f, the DownValues of f are automatically ...
