# Questions tagged [sorting]

Questions on the sorting/ordering functions of Mathematica (Sort, SortBy, Ordering, etc.).

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### Order imported files by their alteration date

Probably a very easy question, but I could not find the answer, so it would be very nice if you can help me: Let us say I have 10 files, all with the extension .dat...
74 views

### Sorting a matrix except its last row

Given M = {{"Utah", 2}, {"Iowa", 1}, {"Maine", 3}, {"Total", 6}} I want to obtain the reverse-sorted result like this: ...
139 views

### Sort lists of vertices {indegrees, outdegrees} by indegree

in = VertexInDegree[F]; out = VertexOutDegree[F]; I want both in and out to be ordered by in. Example: graph has nodes a,b,c with indegrees 1,2,0 and outdegrees 0,...
111 views

### Sorting a table of vectors with weights [duplicate]

I'm trying to simplify a table, for instance {{1, {4, 2, 0}}, {4, {2, 4, 0}}, {-2, {3, 3, 0}}, {1, {3, 0, 3}}, {-3, {0, 4, 2}}} Here the first column is the "...
3k views

### How do I reassign canonical ordering of symbols?

I have a big polynomial that evaluates to: $$A^2 e^2 \phi ^- \phi ^++A e \phi ^- \phi ^+ c_{2 w} g_Z+\frac{1}{2} A e g h W^- \phi ^+ +\ll13\gg,$$ which is supposed to represent some terms in the ...
680 views

### Sorting a large file

I have some huge logs, which are text files, containing up to a million rows each, and I need them sorted. Because trying to import one obviously makes Mathematica run out of memory, we must rule out ...
443 views

### Re-arranging / selecting of a data table very slow in For loop [duplicate]

My task is quite simple; I have a table of data like M = {{1,2}, {1,3}, {3,4}, {5,1}, {6,9}, {6,8}, {6,1}}; so the table is sorted with respect to the first ...
120 views

### Produce a 1-dimensional list of all unique matrix elements

We have some symbolic matrix m, e.g. m={{1, x, 4 x + y},{0, x y + 4x, 4x},{7 x, x, 4x + x y}} and we want to produce as output a list of all the unique elements ...
744 views

### Rank functions of n by their order of growth

I'd like to rank some functions according to their order of growth (e.g. n^2 < n^3). I'm not sure how to do order of growth in mathematica, so I was trying to ...
725 views

### Sorting lists element by element [duplicate]

I have a problem regarding list sorting. Let's say I have a list of lists obtained using Subsets[], of the form ...
663 views

### Windows Explorer Natural Order

Currently there are a list of notebooks in Windows that I am processing in a folder. Ideally I would like the notebooks to be concated in the same order as how they display in Windows Explorer. I ...
537 views

### How to sort Table/Matrix including legend(Labellings)

I want to sort table including its legend for graph I have table similar to M1 M2 M3 1 5 2 3 1 4 4 2 -10 5 7 11 6 -2 1 ...
219 views

### Problem with Sort - unexpected order with Sqrt [duplicate]

Sort[{13, Sqrt, Sqrt}] (*{13, Sqrt, Sqrt}*) Sort[{13, Sqrt, Sqrt}, #1 < #2 &] (*{Sqrt, Sqrt, 13}*) This seems ...
285 views

### How to get all possible orderings (equal ranks allowed) for given set of $N$ objects?

Hope there is a solution besides the tedious generation of nested loops. (Trying to avoid reinventing the wheel.) Here is an example with $N = 3$ objects. There are $13$ needed orderings (first ...
389 views

### Another Sort with multiple criterion

I have a list ...
1k views

### Properly ordering the output of FileNames for a directory consisting of files with consecutive integer names [duplicate]

Say I have a number of files in a directory at some location (C:\dir1\dir2\dir3...), and I pull an array of strings corresponding to the file names with the command: ...
367 views

### Sorting a matrix alphanumerically

Somewhat related to Sort matrix by columns and rows without changing them, but more general. I'd like to sort a square matrix (a 3 by 3 in my case, but surely the general solution will treat any), ...
163 views

### Ordering under assumptions

I have a three-element list which contains inverses of a function u, like so: ...
250 views

### Why does Sort fail in this simple example?

I'm sure I'll be embarrassed by the answer, but I don't understand why I get the following result: list = {{9, "b"}, {4, "a"}, {7, "k4"}, {6, "k3"}, {5, "w"}} ...
928 views

### Sort+Union on a list

Probably this is too trivial question for this forum but for some reason I am not getting it on my Mathematica 7 so far. I have a list ...
474 views

### Sorting a list of triplets by first element of each triplet fails

In the last line of code, I´m trying to order the matrix by the first column. I want to store in the Array t2tlistsorted ( 100 x 3 ), but I can´t. ...
227 views

### Non-canonical re-ordering of nested lists

I have some data in the form: ...
196 views

### Sorting the element in a PDB text file

I am a new user of Mathematica and currently using version 9. I want to rearrange the element of one PDB text file with respect to another PDB text file. Suppose I have a PDB file like this: ...
335 views

### Using Sort vs SortBy

So I have two lists, A and B. I put them into lists = {A,B}I want to sort A such that Im[#1]<Im[#2]& which I can do fine ...
208 views

### How to tell when a job is too big for the pattern matcher?

Pattern matching is great but it has its limitations. Consider sorting a list of numbers from smallest to largest: ...
130 views

### Confused behavior using Dispatch to sort one list relative to another

I have a need to sort the entries of one list into the same sequence as the entries in a reference list. Because I have rather large lists involving strings, I'm trying to use Dispatch to accomplish ...
3k views

### Sort date list in format DD/MM/YYYY

I have a list of dates (ranging from 2007 to 2012) in the DD/MM/YYYY format and I need to sort this list. My problem is, when I simply use Sort[] I get: ...
944 views

### Sorting function for non commuting bosons

I am trying to write a sorting function which will sort expressions involving products of bosonic objects which do not commute. For example, I can have objects like $a,\ a^\dagger,\ b,\ b^\dagger$ ...
572 views

### Sorting Matrix elements

I have matrix in as shown, consisting of real numbers and 0. How can I sort it to become out as shown? ...
930 views

### How to Sort on row by row basis?

Say I have matrix how to sort on row by row basis to get:
376 views

### Why can't I remove Orderless from Plus?

I am making some random algebra equations, and I want to have the ordering be random too, such that if my random equation generator makes x+1, the output stays <...
274 views

### Sorting list with variable

I want to sort (or sortby) the list. List contains uninitialized variable m and I can assume that m is a Natural number that is much larger then any constant. ...
549 views

### Ranking Function Allowing for Ties

I have a list that I need to be able to assign ranks to individual elements in, giving it a number related to its position if the list were to be sorted, allowing for ties. For example, ...
3k views

### Generating an ordered list of pairs of elements from ordered lists

I have a pair of ordered lists. I want to generate a new ordered list (using the same ordering) of length n by applying a binary operator to pairs of elements, one from each list, along with the index ...
521 views

### Mathematica list element sort

I have a list, say, ...
3k views

### Simple algorithm to find cycles in edge list

I have the edge list of an undirected graph which consists of disjoint "cycles" only. Example: {{1, 2}, {2, 3}, {3, 4}, {4, 1}, {5, 6}, {6, 7}, {7, 5}} Each ...
822 views

### Sorting a list and finding an array of indices that sorts the list

How can I sort a list and also get a list of indices that sort this list? For example: primary list is a a={1,4,6,7,0,2}; sorted list is b ...
351 views

### How to pass composite function list to SortBy?

In order to sort alphanumeric-as-string data of the form {"T3", "T14", "T1", "E2"}, so that "T14" comes after ...