# Questions tagged [sorting]

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

338 questions
Filter by
Sorted by
Tagged with
867 views

### Reproducing a ranking function that behaves like Excel's RANK

I tried to find a function or expression in Mathematica that produces the same output as the RANK function in Excel (see its description here), but unfortunately I ...
226 views

### Problem with Custom Sort/Split/Gather

Please help me Sort/Split/Gather/Group(by) a set of symbolic expressions! (extreme TL;DR at bottom) I have a set of symbols (which represent 2-vectors in a plane, ultimately) and I want to sort/split/...
548 views

### Use of Sort with custom functions

As mentionned in the topic title, I try to apply my own sorting functions to a set of elements via the Sort command. I make here a quick presentation of the subject before. 1) Method We will remain ...
139 views

### Role of Accuracy in numerical evaluations, SplitBy vs GatherBy

This is a follow-up question to this question. I generated a list by substituting the results of a solve[] routine and set: ...
709 views

### GatherBy/SplitBy and Sort a list

So let's say I want to group a list of points based on their distance from the origin. I would do something like: ...
487 views

### Order of importing data from files

I have many text files numbered from 1 to 1 million in numerical order. Within each text file is 5 columns of data (TAB spaced) with many rows. I effectively want to take the minimum value from each ...
92 views

### Can't sort my list numerically for larger numbers than 10 e.g. 1,10,100,2 [duplicate]

I want my files names in real numerical order so 1,2,3,10,12. However it is currently putting them in order like so: 1,10,12,2,3 Input: ...
171 views

...
353 views

### What is wrong with my user-defined ordering function?

I've defined ordering function: myOrderingFunction[arg1_, arg2_] which always return True or ...
148 views

### How to check a clockwise direction for a list of point [closed]

Suppose that we have a list of points and we need to order them in clockwise direction by starting from a special point. I implemented this code to order them but I need to detect if it is ordered in ...
346 views

### Sort by returning positions [duplicate]

How can I computationally efficiently sort a list so as to return the positions and not the actual values at those positions (which SortBy does)?
442 views

### Change Contour Plot Overlap Ordering

I have a contour plot for which I have selected a finite set of contours. However, the contours overlap in some places and I would like to reverse the order in which they are drawn. In other words,...
166 views

### sorting eigenvectors of a final combined matrix

I have two matrices m1 and m2 as below: ...
715 views

### Sort Excel File Natural Order

Preferable without reading and then rewriting an excel(vs the COMLink) file how might I sort an excel file by Natural Order based on a column? This question is similar although probably not as ...
84 views

### Finding correct combination of functions

I am trying to write code where I have an array $S$ or numbers in any order [5,4,2,1,....] Then I have a specific set of functions that I can write. ...
92 views

### Unexpected result from Sort with symbolic values

I think Sort should be able to sort symbolic values that are reducible to numerical values, but this example seems to get a wrong answer (here is a simplified ...
137 views

### Select Only Positive Values and Prepend a Title

I have the following list: ...
1k views

### How to order a list to match the order of another list?

How can I order a list to match the order of anoter list ? For example: Suppose I have the lists x = {3, 1, 5, 7} and ...
138 views

### SortBy behaving strangely with missing data

I'm trying to create a grid that shows the largest data value from a list. What I have mostly works- the problem comes when there is missing data. You can't really tell here, but all of the missing ...
832 views

### How to sort list of mixed types of elements with each type a specified canonical order?

For example, here is a list {{1, "u"}, {6, "d"}, {3, "u"}, {4, "d"}, {2, "u"}, {5, "u"}, {3, "d"}, {1, "d"}, {4, "u"}, {2, "d"}, {5, "d"}, {6, "u"}} The ...
470 views

### Wolfram Language symbols by their Ranks

I'd like to get the top 50, the bottom 50 and an ordered list of all Wolfram Language symbols based on their "Ranks". With ...
1k views

### Sorting in descending order of list [closed]

I have a list m = {{a, 20}, {b, 10}, {c, 50}, {d, 5}, {e, 100}} and I want to apply Sort on this in descending order on ...
181 views

### Sorting and keeping the main format of list numbers [duplicate]

I have a list with these elements: list={1/2 (1 + Sqrt[5]), 1, 1, 1/2 (1 - Sqrt[5]), 0}; I want to sort them with ...
274 views

### Exercise using Sort

I have to order the following list according to the sum of the powers of each element of the list, using the function Sort. ...
214 views

### Sort a list of derivatives

I have a list of variables, both constant and functions of an independent variable, including derivatives. I'd like to sort these by the variable name, rather than the derivative order. For example, ...
79 views

### Reverse order in evaluated list

I solve the following set of ODE and plot solution of S1 vs k2 (Figure 1). ...
16k views

### How to sort colors properly?

I can't seem to be able to sort colors by their hue and perceptual brightness correctly. Here's my current solution, but it's not right; there are all these dark bands: ...
150 views

### Challenging matrix sorting request?

I have an application in mind, and I need to do the following analysis, but am having a high degree of difficulty conceptualizing it in terms of syntax. I understand what I want, but cannot seem to ...
112 views

### How to canonically reorganize a list using only a limited set of manipulations?

I want to canonically reorganize (like Sort) a sequence of four objects seq[a,b,c,d], but the only manipulations allowed are <...
231 views

### Arrangement Order and Multiple Columns Sorting Order of Associations with Missing Keys

I have the following well-formed JSON string ...
1k views

### Lexicographic ordering of lists-of-lists?

I was surprised to discover that Mathematica does not sort lists-of-lists (LLs) lexicographically by default. For example, applying Sort to ...
183 views

### SameQ for unsorted lists

I have to compare two or more lists and check if they are the same, but their elements can be in different position. For instance ...
157 views

### Descending order of Permutations using Select[Tuples[{5, 4, 3, 2, 1}, {3}], OrderedQ]

I was wondering if there is a possible way to still use OrderedQ and get a descending order of permutations: This is Ascending order: ...
67 views

### Sorting orthogonal null space vectors

My program generates orthogonal null space vectors such as this: ...
2k views

### Difference between Sort and SortBy

I was playing with Sort. All examples I have come across so far, i.e Sort[{1, -1, 3, -3, 2, 5}, Abs[#1]<Abs[#2]&] can expressed in a shorter fashion ...
271 views

### Are there any good mass row/column swapping functions for matrices?

I have the following matrix Keeping the 20 row and 20 column fixed (so the 21st rows and columns because I started at 0)...how do I push each row and column back one spot? I need to push the 0th row ...
261 views

### Find list item before first negative value [closed]

If I have a list like this: ...
542 views

### How to sort the list of all possible 3-tuples of elements from list constrained by a condition?

I want to know if there's a way to impose desired condition on Tuple command output. I have generated a list of 3-tuple of elements from {1,2,3,4,5,6,7,8,9,10} ...
630 views

### Sort Unicode characters

Sorting ASCII phrases works fine: Sort[{"albatrob", "abo", "dict", "star", "mangel", "m"}] (*{"abo", "albatrob", "dict", "m", "mangel", "star"}*) But unless I'm ...
382 views

### Is there an inequality operator (Less, Greater) for lists of elements (as opposed to elements)?

Like multi-column sorting. For example, {1,3,5} > {1,2,5} would return True, while ...
290 views

### Collision detection algorithm (discrete) with sweep and prune algorithm for periodic boundary conditions

EDIT: Question Updated with solution approach, but solution much slower than original implementation. Any ideas to speed up implementation? In the discussion on collision detection (see here) I asked ...
1k views

### Finding minimum of a list of pairs

Sometimes I need to find the Min of a list, whose elements are lists (say of two elements, a pair). Given that Min does not have the option to indicate a sorting function like Sort, I elaborated the ...
146 views

### Error with using SortBy in a Map [closed]

I have a data set in the following format: SomeData = {{a, 1, 2}, {b, 2, 3}, {c, 3, 4}, {b, 1, 9}, {c, 1, 10}, {a, 2, 3}, {a, 3, 8}, {b, 3, 4}, {c, 2, 9}}; The ...
98 views

### How do I reassign canonical ordering of special expressions?

1. Default behavior of Sort Note: this peculiarity is described in a comment to a related question at StackOverflow but I think it's worth restating here at mma.sx. It is estabilished in ...
40 views

### Sort giving unexpected output! [duplicate]

I want to perform sorting on a list of strings, If i take for example the list s s = {"test9","test8","test10"}; If I perform ...
218 views

### Importing, sorting and exporting lists

I have several TSV lists (.txt) of something like 2000*2000 numerics (e.g. 1.8645) to import ...
269 views

### ordered tree data structure

I have a map $f:X\to \mathbb{N}$ and I wish to find $x,x'\in X$ such that $f(x)=f(x')$. Since such elements are rare, I will have to check very many elements and perform many comparisons, so I suspect ...
107 views

### Breaking term order ties [duplicate]

I am interested in creating a table with positive Gaussian integers listed in order based on their norms, with ties broken by lex order. So far I have ...