Tutorial by Examples: in

TextInputDialog allows the to ask the user to input a single String. TextInputDialog dialog = new TextInputDialog("42"); dialog.setHeaderText("Input your favourite int."); dialog.setTitle("Favourite number?"); dialog.setContentText("Your favourite int: ");...
Dim aList as New List(Of String) aList.Add("one") aList.Add("two") aList.Add("three") For Each str As String in aList System.Console.WriteLine(str) Next Produces the following output: one two three Another option, would be to loop through using the ...
Related to Monads are F# computation expressions (CE). A programmer typically implements a CE to provide an alternative approach to chaining Monads, ie instead of this: let v = m >>= fun x -> n >>= fun y -> return_ (x, y) You can write this: let v = ce { let! x = m ...
Overview: The default data type for numeric arrays in MATLAB is double. double is a floating point representation of numbers, and this format takes 8 bytes (or 64 bits) per value. In some cases, where e.g. dealing only with integers or when numerical instability is not an imminent issue, such high ...
Most programming languages, including F#, evaluate computations immediately in accord with a model called Strict Evaluation. However, in Lazy Evaluation, computations are not evaluated until they are needed. F# allows us to use lazy evaluation through both the lazy keyword and sequences. // define ...
F#, like most programming languages, uses Strict Evaluation by default. In Strict Evaluation, computations are executed immediately. In contrast, Lazy Evaluation, defers execution of computations until their results are needed. Moreover, the results of a computation under Lazy Evaluation are cached,...
Emacs's user interface uses terms that were coined early and can be unsettling to users used to a more modern terminology. Frame In Emacs, what is otherwise called a window (the area of the display used by a program) is called a frame. Emacs starts using one frame, though additional frames may b...
Sometimes it is desirable to evaluate a nullable expression in an if-else fashion. The elvis operator, ?:, can be used in Kotlin for such a situation. For instance: val value: String = data?.first() ?: "Nothing here." The expression above returns "Nothing here" if data?.firs...
This is a specialized field, used to store binary data. It only accepts bytes. Data is base64 serialized upon storage. As this is storing binary data, this field cannot be used in a filter. from django.db import models class MyModel(models.Model): my_binary_data = models.BinaryField() ...
Detailed instructions on getting xquery set up or installed.
In real world, connection and server delays could occur, to simulate delays in development environment Meteor._sleepForMs(ms); could be used Meteor.publish('USER_DATA', function() { Meteor._sleepForMs(3000); // Simulate 3 seconds delay return Meteor.users.find({}); });
select '123' * 2; To make the multiplication with 2 MySQL automatically converts the string 123 into a number. Return value: 246 The conversion to a number starts from left to right. If the conversion is not possible the result is 0 select '123ABC' * 2 Return value: 246 select 'A...
To load an image and place it on the canvas var image = new Image(); // see note on creating an image image.src = "imageURL"; image.onload = function(){ ctx.drawImage(this,0,0); } Creating an image There are several ways to create an image new Image() document.createEleme...
@Entity class Note { @Id Integer id; @Basic String note; @Transient String parsedNote; String readParsedNote() { if (parsedNote == null) { /* initialize from note */ } return parsedNote; } } If your class needs fields that should ...
Suppose we want to get all product categories with total sales greater than 20. Here is a query without Common Table Expressions: SELECT category.description, sum(product.price) as total_sales FROM sale LEFT JOIN product on sale.product_id = product.id LEFT JOIN category on product.category_id ...
SELECT x, ... FROM ( SELECT y, ... FROM ... ) AS a JOIN tbl ON tbl.x = a.y WHERE ... This will evaluate the subquery into a temp table, then JOIN that to tbl. Prior to 5.6, there could not be an index on the temp table. So, this was potentially very inefficient: SELECT ... ...
For...Next Using the iterator variable as the index number is the fastest way to iterate the elements of an array: Dim items As Variant items = Array(0, 1, 2, 3) Dim index As Integer For index = LBound(items) To UBound(items) 'assumes value can be implicitly converted to a String: D...
With a column of one of the string types, named my_date_field with a value such as [the string] 07/25/2016, the following statement demonstrates the use of the STR_TO_DATE function: SELECT STR_TO_DATE(my_date_field, '%m/%d/%Y') FROM my_table; You could use this function as part of WHERE clause a...
The following will echo each line in the file C:\scripts\testFile.txt. Blank lines will not be processed. for /F "tokens=*" %%A in (C:\scripts\testFile.txt) do ( echo %%A rem do other stuff here ) More advanced example shows, how derived in FOR loop from a restricted files set...
From command line: cpan -l From a Perl script: use ExtUtils::Installed; my $inst = ExtUtils::Installed->new(); my @modules = $inst->modules();

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