sorting - F# - Sort a matrix containing tuples -

-

I did not find a way to sort the values ​​contained in the column of the following matrix of tuples: Matrix & lt; Float * float & gt; = Matrix [[(1.0, 145.0); (1.0, 45.0); (1.0, 130.0); (1.0, 30.0); (1.0, 130.0)] [(2.0, 45.0); (2.0, 45.0); (2.0, 30.0); (2.0, 30.0); (2.0, 30.0)] [(3.0, 130.0); (3.0, 30.0); (3.0, 145.0); (3.0, 45.0); (3.0, 130.0)] [(4.0, 30.0); (4.0, 30.0); (4.0, 45.0); (4.0, 45.0); (4.0, 30.0)] [(5.0, 130.0); (5.0, 30.0); (5.0, 130.0); (5.0, 30.0); I would like to sort each column on the basis of the second element of Tupal (5.0, 145.0)]]

Will be given: 

  matrix [[(1.0, 145.0); (1.0, 45.0); (3.0, 145.0); (3.0, 45.0); (5.0, 145.0)] [(3.0, 130.0); (2.0, 45.0); (1.0, 130.0); (4.0, 45.0); (1.0, 130.0)] [(5.0, 130.0); (3.0, 30.0); (5.0, 130.0); (1.0, 30.0); (3.0, 130.0)] [(2.0, 45.0); (4.0, 30.0); (4.0, 45.0); (2.0, 30.0); (2.0, 30.0)] [(4.0, 30.0); (5.0, 30.0); (2.0, 30.0); (5.0, 30.0); Thank you in advance!   
 
   
 P> In my experience, when arrays (2D and / Or matrix), then I came to know that working internally with arrays is often the fastest way.   
 For example, in the way of destabilizing the outlook of Daniel and Ankur:  
  Let's start temporary astrobolic f (M: matrix & lt; 'T & gt; ) = Column = = [| 0 for C. .. m.NumCols - 1 - & gt; M. Column C | & Gt; Vector Generic Torre |] for C in 0 .. m.NumCols - 1 column. [C] | & Gt; Array.sortInPlace By f Matrix.Generic.init (m.NumRows) (m.NumCols) (Fun RC -> Columns. [C]. [R])   
 Matrix columns (For an array of 'A [] [], no' [[]] and sorted the in-place on each column, after that, I filled out a new matrix with the sorted result. Note that the original matrix Cluttering: Column Array comes from the copies of the column vector (Vector Toure creates a new array).  
 This approach is fast because in it There is no need for transfers, instead of type of columns, and keeping all array-oriented, intermediate list structures do not require any conversions. I suspect that this can be made faster if the matrix module has' [ Even with conversion from [/] [], even though it is probably not really suitable for the matrix.  
 Also, know: you can compare the structural comparison of F # to the other Element can sort by descending, the first element of ascending:  
 Example:  
  & gt; MutableSortByCol (Fun (A, B) - & gt; (-b, a)) ;; This value: Matrix & lt; Float * float & gt; = Matrix [[(1.0, 145.0); (1.0, 45.0); (3.0, 145.0); (3.0, 45.0); (5.0, 145.0)] [(3.0, 130.0); (2.0, 45.0); (1.0, 130.0); (4.0, 45.0); (1.0, 130.0)] [(5.0, 130.0); (3.0, 30.0); (5.0, 130.0); (1.0, 30.0); (3.0, 130.0)] [(2.0, 45.0); (4.0, 30.0); (4.0, 45.0); (2.0, 30.0); (2.0, 30.0)] [(4.0, 30.0); (5.0, 30.0); (2.0, 30.0); (5.0, 30.0); (4.0, 30.0)]]

Comments

Post a Comment

Popular posts from this blog

mysql - BLOB/TEXT column 'value' used in key specification without a key length -

-
I have developed an extension which works up to 1.6 on Magren (I'm trying Enterprise Edition, And I think the community is the same problem, because it is the same code). In my install script, I see the $ installer-> gt; CreateEntityTables ($ this- & gt; getTable ('alphanum / info')); The installation is done until it is not in the _text unit table. It crashed there! It turns out that when I log in to SQL and run it via PHPmyadmin, then this error is: Blob / Text column 'value' is used without the key 'key' . I saw the code there, and this is what is trying to create an index on the value column: -> addIndex ($ this- & gt; getIdxName ($ eavTableName, array ( 'attribute_id array (' attribute_id ',' value ')) - & gt; addIndex ($ this- & gt; getIdxName ($ eavTableName, array (' entity_type_id ' , 'Value')), array ('entity_type_id', 'value')) If there is no if statement is n...
Read more

c# - Using Vici cool Storage with monodroid -

-
Oh, for the moment I am not sure how it is officially supported, but for the success of the people Using Monodroid Vic Cool Storage I am able to leave and compile assemblies in my project, but while trying to use some classes, the errors of time have to be gathered. Especially when trying to connect like the example for Mono Touch string dbName = path. Cobain (environment. Gatefolder path (environment specialfolder personal), "mydb.db3"); // The following line will be called coolestation, where is the database, // to make it if it does not exist, and call a delegate that creates the necessary tables (only when the database file was newly created //) CSConfig.SetDB (DbName, true, () => {CSDatabase.ExecuteNonQuery ("Subscriber Integer Primary Key Attribute, Name Text (50) No, Number, Date First Text (30)");); There is no difference when I try to use the methods of CSConfig and when I cscfif If I try to pass 3 aggregates to STDB (3) then I get the invalid ...
Read more

python - referencing a variable in another function? -

-
I am an experienced TCL developer and write my own processes to help myself. I call it a proc i callVar, print out the value of the variable in a certain format, so I know that it is variable and what is the value "set foo 1; putVar foo" result 'foo = "1" I want to do the same thing in Python, but I can not find the answer :( In TCL I use the up command because when I pass the name of the variable, then I can see the value at the top. . I understand that an advanced light in the dragon There is no mechanism of r, but with its introspection capability, I would think that this is something trivial, but I am not getting the answer anywhere. It seems that this should work: and expanded: def foo (): y = "Hello World" printwor ("y") foo () y = "Hello World " You can, but you should not do so if your code is correct If is needed , then there is something wrong with your design, and you should probably use the dictionar...
Read more