Tutorial by Examples: re

When an object is exposed to the template context, its arguments-less methods are available. This is useful when these functions are "getters". But it can be hazardeous if these methods alter some data or have some side effects. Eventhough you likely trust the template writer, he may not b...

$> pwd /home/myUserHome $> cd .. $> pwd /home will print the current path to the console.

When working with large files, you can use the System.IO.File.ReadLines method to read all lines from a file into an IEnumerable<string>. This is similar to System.IO.File.ReadAllLines, except that it doesn't load the whole file into memory at once, making it more efficient when working with l...

File static class By using Create method of the File static class we can create files. Method creates the file at the given path, at the same time it opens the file and gives us the FileStream of the file. Make sure you close the file after you are done with it. ex1: var fileStream1 = File.Create...

SQL has various join types to specify whether (non-)matching rows are included in the result: INNER JOIN, LEFT OUTER JOIN, RIGHT OUTER JOIN, and FULL OUTER JOIN (the INNER and OUTER keywords are optional). The figure below underlines the differences between these types of joins: the blue area repres...

Pre-processing in caret is done through the preProcess() function. Given a matrix or data frame type object x, preProcess() applies transformations on the training data which can then be applied to testing data. The heart of the preProcess() function is the method argument. Method operations are ap...

To know the path of the directory your file is in you can use: Esc to enter command mode :pwd This will print the path to the directory at the bottom of the editor, like this I'm a ninja ~ ~ ~ ~ ~ /home/ubuntu/myfolder 1,5 All Now...

Interface declaration for downloading a file public interface ApiInterface { @GET("movie/now_playing") Call<MovieResponse> getNowPlayingMovies(@Query("api_key") String apiKey, @Query("page") int page); // option 1: a resource relative to your bas...

Returns a string (varchar or nvarchar) where all occurrences of a specified sub string is replaced with another sub string. Parameters: string expression. This is the string that would be searched. It can be a character or binary data type. pattern. This is the sub string that would be replaced...

In Normal, type the following to delete a range of lines into a named register :10,20d a This will delete lines 10,20 in register "a. We can verify this by typing :reg This will show the text that was delete in register "a. To paste the contents in "a, just type "ap ...

If a recursive call goes "too deep", this results in a StackOverflowError. Java allocates a new frame for every method call on its thread's stack. However, the space of each thread's stack is limited. Too many frames on the stack leads to the Stack Overflow (SO). Example public static vo...

Since Laravel version 5.2.31 the web middleware is applied by default within the RouteServiceProvider (https://github.com/laravel/laravel/commit/5c30c98db96459b4cc878d085490e4677b0b67ed) In app/Providers/RouteServiceProvider.php you will find the following functions which apply the middleware on ev...

To print the directory stack, use the command pushd without any parameters: @echo off cd C:\example\ pushd one pushd ..\two pushd ..\.. pushd echo Current Directory: %cd% echo: popd pushd three pushd echo Current Directory: %cd% Output: C:\example\two ...

private static final String IMGUR_CLIENT_ID = "..."; private static final MediaType MEDIA_TYPE_PNG = MediaType.parse("image/png"); private final OkHttpClient client = new OkHttpClient(); public void run() throws Exception { // Use the imgur image upload API as ...

It is unlikely for a developer to not come across a deprecated API during a development process. A deprecated program element is one that programmers are discouraged from using, typically because it is dangerous, or because a better alternative exists. Compilers and analyzers (like LINT) warn when a...

This is a huge topic, but it is also the most important "performance" issue. The main lesson for a novice is to learn of "composite" indexes. Here's a quick example: INDEX(last_name, first_name) is excellent for these: WHERE last_name = '...' WHERE first_name = '...' AND ...

innodb_buffer_pool_size should be about 70% of available RAM.

You can change the url of an existing remote by the command git remote set-url remote-name url

Example below shows how to create a BroadcastReceiver which is able to receive BOOT_COMPLETED events. This way, you are able to start a Service or start an Activity as soon device was powered up. Also, you can use BOOT_COMPLETED events to restore your alarms since they are destroyed when device is ...

For the sake of this example, let us assume that we have a server for handling the POST requests that we will be making from our Android app: // User input data. String email = "[email protected]"; String password = "123"; // Our server URL for handling POST requests. String UR...