Tutorial by Examples: el

One of the most straight forward way of making an LED blink is: turn it on, wait a bit, turn it off, wait again, and repeat endlessly: // set constants for blinking the built-in LED at 1 Hz #define OUTPIN LED_BUILTIN #define PERIOD 500 void setup() { pinMode(OUTPIN, OUTPUT); // sets t...

The elapsedMillis library provides a class with the same name that keeps track of the time that passed since it was created or set to a certain value: #include <elapsedMillis.h> #define OUTPIN LED_BUILTIN #define PERIOD 500 elapsedMillis ledTime; bool ledState = false; void setup...

#include <elapsedMillis.h> void setup() { Serial.begin(115200); elapsedMillis msTimer; elapsedMicros usTimer; long int dt = 500; delay(dt); long int us = usTimer; long int ms = msTimer; Serial.print("delay(");Serial.print(dt);Serial.println(") to...

Pattern matching can be used effectively with awk as it controls the actions that follows it i.e. { pattern } { action }. One cool use of the pattern-matching is to select multiple between two patterns in a file say patternA and patternB $ awk '/patternA/,/patternB/' file Assume my file contents...

This trick helps you select an element using the ID as a value for an attribute selector to avoid the high specificity of the ID selector. HTML: <div id="element">...</div> CSS #element { ... } /* High specificity will override many selectors */ [id="element&quo...

The DatePicker class has a property, SelectedDate, which enable you to get or set the selected date. If there is none selected, it means its value will be null. if (datePicker.SelectedDate == null) { // Do what you have to do }

var client = new MongoClient("mongodb://localhost:27017"); var database = client.GetDatabase("test"); var collection = database.GetCollection < Interactions > ("Interactions"); var result = IMongoCollectionExtensions .AsQueryable(collection) ...

var client = new MongoClient("mongodb://localhost:27017"); var database = client.GetDatabase("test"); var collection = database.GetCollection < Interactions > ("Interactions"); collection.DeleteOne(s => s.SiteName == "New Example");

DELETE FROM Helloworlds This will delete all the data from the table. The table will contain no rows after you run this code. Unlike DROP TABLE, this preserves the table itself and its structure and you can continue to insert new rows into that table. Another way to delete all rows in table is ...

Often you will want to perform asynchronous operations in parallel. There is direct syntax that supports this in the async/await proposal, but since await will wait for a promise, you can wrap multiple promises together in Promise.all to wait for them: // Not in parallel async function getFriend...

Modules can be required without using relative paths by putting them in a special directory called node_modules. For example, to require a module called foo from a file index.js, you can use the following directory structure: index.js \- node_modules \- foo |- foo.js \- package.json ...

Nesting is great for keeping related selectors together to make it easier for future developers to understand your code. The parent selector, represented by an ampersand ("&") can help do that in more complex situations. There are several ways its can be used. Create a new selector th...

Swift 2 import UIKit extension UIDevice { var modelName: String { var systemInfo = utsname() uname(&systemInfo) let machineMirror = Mirror(reflecting: systemInfo.machine) let identifier = machineMirror.children.reduce("") { identifier, ele...

Individual elements can be accessed through indexes. Python arrays are zero-indexed. Here is an example : my_array = array('i', [1,2,3,4,5]) print(my_array[1]) # 2 print(my_array[2]) # 3 print(my_array[0]) # 1

Here is an example : my_array = array('i', [1,2,3,4,5]) my_array.remove(4) # array('i', [1, 2, 3, 5]) We see that the element 4 was removed from the array.

pop removes the last element from the array. Here is an example : my_array = array('i', [1,2,3,4,5]) my_array.pop() # array('i', [1, 2, 3, 4]) So we see that the last element (5) was popped out of array.

index() returns first index of the matching value. Remember that arrays are zero-indexed. my_array = array('i', [1,2,3,4,5]) print(my_array.index(5)) # 5 my_array = array('i', [1,2,3,3,5]) print(my_array.index(3)) # 3 Note in that second example that only one index was returned, even though...

count() will return the number of times and element appears in an array. In the following example we see that the value 3 occurs twice. my_array = array('i', [1,2,3,3,5]) my_array.count(3) # 2

When you need a Python list object, you can utilize the tolist() method to convert your array to a list. my_array = array('i', [1,2,3,4,5]) c = my_array.tolist() # [1, 2, 3, 4, 5]

Sometimes, if an action should be bind to a collection view's cell selection, you have to implement the UICollectionViewDelegate protocol. Let's say the collection view is inside a UIViewController MyViewController. Objective-C In your MyViewController.h declares that it implements the UICollecti...