Tutorial by Examples: le

To support a given application, you often create a new role and database to match. The shell commands to run would be these: $ createuser -P blogger Enter password for the new role: ******** Enter it again: ******** $ createdb -O blogger blogger This assumes that pg_hba.conf has been prope...

Table file with header, footer, row names, and index column: file: table.txt This is a header that discusses the table file to show space in a generic table file index name occupation 1 Alice Salesman 2 Bob Engineer 3 Charlie Janitor This is a footer becaus...

Using the default constructor T variable = Activator.CreateInstance(typeof(T)); Using parameterized constructor T variable = Activator.CreateInstance(typeof(T), arg1, arg2);

Occasionally you'd want to catch an exception and throw it from a different thread or method while preserving the original exception stack. This can be done with ExceptionDispatchInfo: using System.Runtime.ExceptionServices; void Main() { ExceptionDispatchInfo capturedException = null; ...

.NET Framework defines a interface for types requiring a tear-down method: public interface IDisposable { void Dispose(); } Dispose() is primarily used for cleaning up resources, like unmanaged references. However, it can also be useful to force the disposing of other resources even though ...

Messages printed from NSLog are displayed on Console.app even in the release build of your app, which doesn't make sense for printouts that are only useful for debugging. To fix this, you can use this macro for debug logging instead of NSLog. #ifdef DEBUG #define DLog(...) NSLog(__VA_ARGS__) #els...

To use Leaflet, load its stylesheet and JavaScript file to your page: <link rel="stylesheet" href="/css/leaflet.css" /> <script src="/js/leaflet.js"></script> These resources can be downloaded from a variety of locations such as Leaflet's homepage...

First, import the libraries that work with files: from os import listdir from os.path import isfile, join, exists A helper function to read only files from a directory: def get_files(path): for file in listdir(path): full_path = join(path, file) if isfile(full_path): ...

// *** Case Insensitive comparison with exact title match *** NSPredicate *filterByNameCIS = [NSPredicate predicateWithFormat:@"self.title LIKE[cd] %@",@"Tom and Jerry"]; NSLog(@"Filter By Name(CIS) : %@",[array filteredArrayUsingPredicate:filterByNameCIS]);

// *** Case sensitive with exact title match *** NSPredicate *filterByNameCS = [NSPredicate predicateWithFormat:@"self.title = %@",@"Tom and Jerry"]; NSLog(@"Filter By Name(CS) : %@",[array filteredArrayUsingPredicate:filterByNameCS]);

An enumeration is a user-defined data type consists of integral constants and each integral constant is given a name. Keyword enum is used to define enumerated data type. If you use enum instead of int or string/ char*, you increase compile-time checking and avoid errors from passing in invalid con...

There are times in which it is desirable to consolidate factor levels into fewer groups, perhaps because of sparse data in one of the categories. It may also occur when you have varying spellings or capitalization of the category names. Consider as an example the factor set.seed(1) colorful <...

To iterate over several generators in parallel, use the zip builtin: for x, y in zip(a,b): print(x,y) Results in: 1 x 2 y 3 z In python 2 you should use itertools.izip instead. Here we can also see that the all the zip functions yield tuples. Note that zip will stop iterating as soon...

public bool IsTypeNullable<T>() { return Nullable.GetUnderlyingType( typeof(T) )!=null; }

// define url let url = NSURL(string: "https://urlToGet.com") //create a task to get data from a url let task = NSURLSession.sharedSession().dataTaskWithURL(url!) { /*inside this block, we have access to NSData *data, NSURLResponse *response, and NSError...

from container to host docker cp CONTAINER_NAME:PATH_IN_CONTAINER PATH_IN_HOST from host to container docker cp PATH_IN_HOST CONTAINER_NAME:PATH_IN_CONTAINER If I use jess/transmission from https://hub.docker.com/r/jess/transmission/builds/bsn7eqxrkzrhxazcuytbmzp/ , the files in the contai...

You can use a For Each...Next loop to iterate through any IEnumerable type. This includes arrays, lists, and anything else that may be of type IEnumerable or returns an IEnumerable. An example of looping through a DataTable's Rows property would look like this: For Each row As DataRow In DataTable...

Syntactically, a tuple is a comma-separated list of values: t = 'a', 'b', 'c', 'd', 'e' Although not necessary, it is common to enclose tuples in parentheses: t = ('a', 'b', 'c', 'd', 'e') Create an empty tuple with parentheses: t0 = () type(t0) # <type 'tuple'> To crea...

Dependencies npm i -D webpack babel-loader webpack.config.js const path = require('path'); module.exports = { entry: { app: ['babel-polyfill', './src/'], }, output: { path: __dirname, filename: './dist/[name].js', }, resolve: { extensions: ['', '.js'], }...

Required modules npm install --save-dev webpack extract-text-webpack-plugin file-loader css-loader style-loader Folder structure . └── assets    ├── css     ├── images    └── js webpack.config.js const webpack = require('webpack'); const ExtractTextPlugin = require('extract-text-webp...