Tutorial by Examples: b

Dart has a robust async library, with Future, Stream, and more. However, sometimes you might run into an asynchronous API that uses callbacks instead of Futures. To bridge the gap between callbacks and Futures, Dart offers the Completer class. You can use a Completer to convert a callback into a Fut...

The following example creates a canvas with 2 points and 1 line in between. You will be able to move the point and the line around. from kivy.app import App from kivy.graphics import Ellipse, Line from kivy.uix.boxlayout import BoxLayout class CustomLayout(BoxLayout): def __init__(se...

In many Excel applications, the VBA code takes actions directed at the workbook in which it's contained. You save that workbook with a ".xlsm" extension and the VBA macros only focus on the worksheets and data within. However, there are often times when you need to combine or merge data fr...

It's a VBA Best Practice to always specify which workbook your VBA code refers. If this specification is omitted, then VBA assumes the code is directed at the currently active workbook (ActiveWorkbook). '--- the currently active workbook (and worksheet) is implied Range("A1").value = 3.1...

If you want to access a workbook that's already open, then getting the assignment from the Workbooks collection is straightforward: dim myWB as Workbook Set myWB = Workbooks("UsuallyFullPathnameOfWorkbook.xlsx") If you want to create a new workbook, then use the Workbooks collection o...

Often saving new data in an existing workbook using VBA will cause a pop-up question noting that the file already exists. To prevent this pop-up question, you have to suppress these types of alerts. Application.DisplayAlerts = False 'disable user prompt to overwrite file myWB.SaveAs FileNa...

The "factory default" number of worksheets created in a new Excel workbook is generally set to three. Your VBA code can explicitly set the number of worksheets in a new workbook. '--- save the current Excel global setting With Application Dim oldSheetsCount As Integer oldSheets...

When the GADTs extension is enabled, besides regular data declarations, you can also declare generalized algebraic datatypes as follows: data DataType a where Constr1 :: Int -> a -> Foo a -> DataType a Constr2 :: Show a => a -> DataType a Constr3 :: DataType Int A G...

Step 1: Install the SDK You can install the SDK manually or via CocoaPods. The latter option is highly recommended. Put these lines in Podfile: target 'MyApp' do use_frameworks! pod 'FBSDKCoreKit' pod 'FBSDKLoginKit' pod 'FBSDKShareKit' end Run pod install in the terminal and op...

This program copies a file using readable and a writable stream with the pipe() function provided by the stream class // require the file system module var fs = require('fs'); /* Create readable stream to file in current directory named 'node.txt' Use utf8 encoding Read the data...

Multiple database cursors can be published from the same publication method by returning an array of cursors. The "children" cursors will be treated as joins and will not be reactive. Meteor.publish('USER_THREAD', function(postId) { let userId = this.userId; let comments = Comm...

app.js const readline = require('readline'); const fs = require('fs'); var file = 'path.to.file'; var rl = readline.createInterface({ input: fs.createReadStream(file), output: process.stdout, terminal: false }); rl.on('line', function (line) { console.log(line) // print...

The following example shows how to merge two arrays into one associative array, where the key values will be the items of the first array, and the values will be from the second: $array_one = ['key1', 'key2', 'key3']; $array_two = ['value1', 'value2', 'value3']; $array_three = array_combine($ar...

If you want to hide a keyboard by tap outside of it, it's possible to use this hacky trick (works only with Objective-C): - (void)viewDidLoad { [super viewDidLoad]; // dismiss keyboard when tap outside a text field UITapGestureRecognizer *tapGestureRecognizer = [[UITapGestureRecogn...

Get Focus Swift textField.becomeFirstResponder() Objective-C [textField becomeFirstResponder]; Resign Swift textField.resignFirstResponder() Objective-C [textField resignFirstResponder];

vagrant up By default the box will be provisioned.

vagrant up --no-provision

vagrant provision

UIStoryboard *storyboard = [UIStoryboard storyboardWithName:@"Main" bundle:nil]; With an Identifier: Give the scene a Storyboard ID within the identity inspector of the storyboard. Instantiate in code: UIViewController *controller = [storyboard instantiateViewControllerWithIdentifi...

[<Measure>] type m // meters [<Measure>] type cm // centimeters // Conversion factor let cmInM = 100<cm/m> let distanceInM = 1<m> let distanceInCM = distanceInM * cmInM // 100<cm> // Conversion function let cmToM (x : int<cm>) = x / 100<cm/m> l...