Tutorial by Examples: r

You can declare a UIFont as follows: var font: UIFont! UIFont has more init() methods: UIFont.init(descriptor: UIFontDescriptor, size: CGFloat) UIFont.init(name: String, size: CGFloat) Therefore, you can initialize a UIFont like this: let font = UIFont(name: "Helvetica Neue", s...

Coercion happens with data types in R, often implicitly, so that the data can accommodate all the values. For example, x = 1:3 x [1] 1 2 3 typeof(x) #[1] "integer" x[2] = "hi" x #[1] "1" "hi" "3" typeof(x) #[1] "character" ...

The Builder Pattern decouples the creation of the object from the object itself. The main idea behind is that an object does not have to be responsible for its own creation. The correct and valid assembly of a complex object may be a complicated task in itself, so this task can be delegated to anoth...

Used for the RAII style acquiring of try locks, timed try locks and recursive locks. std::unique_lock allows for exclusive ownership of mutexes. std::shared_lock allows for shared ownership of mutexes. Several threads can hold std::shared_locks on a std::shared_mutex. Available from C++ 14. std:...

A shared_lock can be used in conjunction with a unique lock to allow multiple readers and exclusive writers. #include <unordered_map> #include <mutex> #include <shared_mutex> #include <thread> #include <string> #include <iostream> class PhoneBook { ...

Renaming the server.php to index.php Copy the .htaccess from public folder to root folder Changing .htaccess a bit as follows for statics: RewriteEngine On RewriteCond %{REQUEST_FILENAME} !-d RewriteRule ^(.*)/$ /$1 [L,R=301] RewriteCond %{REQUEST_URI} !(\.css|\.js|\.png|\.jpg|\.gif|ro...

Kernel manages operating system resources. User program can only access to those resources by making system calls to the kernel. System call is similar to an API of kernel, which in term, runs kernel tasks your program needs. str = "something" // run on user space x = x + 1 // run on use...

Use top command to exam CPU time allocation between user space and kernel space. Explanation: 24.8 us (user space): 24.8% of CPU time is spent on user process. 0.5 sy (system): 0.5% of CPU time is spent on kernel space. ni (niceness): the ratio of CPU time spent on low priority processes. i...

Use time command. time ./perl-timeout-example 100.100.100 We could not ping the desired address! real 0m5.0013s user 0m0.004s sys 0m0.008s Real: Total time from start to finish of the call, including the CPU time spent on other processes. User: The amount of CPU time spent i...

Steps to copy heroku database to local database: 1. Run copy process in terminal: heroku pg:pull DATABASE_URL change_to_your_data_base_name --app change_to_your_app_name 2. Change db owner using this query: GRANT ALL PRIVILEGES ON DATABASE change_to_your_data_base_name to change_to_your_user; A...

Disabling calculation of the worksheet can decrease running time of the macro significantly. Moreover, disabling events, screen updating and page breaks would be beneficial. Following Sub can be used in any macro for this purpose. Sub OptimizeVBA(isOn As Boolean) Application.Calculation = IIf(...

$service = new NetSuiteService(); $search = new TransactionSearchAdvanced(); $internalId = '123';//transaction internalId $search->criteria->basic->internalIdNumber->searchValue = $internalId; $search->criteria->basic->internalIdNumber->operator = "equalTo"; ...

Often you want to lock the entire object while you perform multiple operations on it. For example, if you need to examine or modify the object using iterators. Whenever you need to call multiple member functions it is generally more efficient to lock the whole object rather than individual member fu...

You can define the signing configuration to sign the apk in the build.gradle file. You can define: storeFile : the keystore file storePassword: the keystore password keyAlias: a key alias name keyPassword: A key alias password You have to define the signingConfigs block to create a signin...

When one with typeof operator one gets type object it falls into somewhat wast category... In practice you might need to narrow it down to what sort of 'object' it actually is and one way to do it is to use object constructor name to get what flavour of object it actually is: Object.prototype.toSt...

platform.ready().then(() => { // Okay, so the platform is ready and our plugins are available. // Here you can do any higher level native things you might need. var url= "https://blog.knoldus.com/"; var browserRef = window.cordova.InAppBrowser.open(url, &qu...

Instead of this (unfortunately too often seen in the real code) "masterpiece": function isEven(n) { return n % 2 == 0; } function isOdd(n) { if (isEven(n)) { return false; } else { return true; } } You can do the parity check much more effecti...

var a = 11, b = 22; a = a ^ b; b = a ^ b; a = a ^ b; console.log("a = " + a + "; b = " + b);// a is now 22 and b is now 11

We can create dynamic component and get the instances of component into an array and finally rendered it on template. For example, we can can consider two widget component, ChartWidget and PatientWidget which extended the class WidgetComponent that I wanted to add in the container. ChartWidget.ts ...

<iframe "id="iframe_Login1"> <iframe "id="iframe_Login2"> <iframe "id="iframe_Login3"> </iframe> </iframe> </iframe> To switch into frame in selenium use swithTo() and frame()...