Tutorial by Examples: re

Functions always establish a block around the body. This block has the same name as the function name. This means you can use RETURN-FROM with this block name to return from the function and return values. You should avoid returning early whenever possible. (defun foobar (x y) (when (oddp x) ...

The search pattern can also be a regular expression. Running: grep '^[A-Z]' someFile.txt When someFile.txt contains: fred 14 m foo sam 68 m bar christina 83 f baz bob 22 m qux Sam 41 m quux Will produce the output: Sam 41 m quux since this is the only line in someFile.txt starting wi...

sp_who2 This procedure can be used to find information on current SQL server sessions. Since it is a procedure, it's often helpful to store the results into a temporary table or table variable so one can order, filter, and transform the results as needed. The below can be used for a queryable v...

To create a mixin use the @mixin directive. @mixin default-box ($color, $borderColor) { color: $color; border: 1px solid $borderColor; clear: both; display: block; margin: 5px 0; padding: 5px 10px; } You can specify a list of arguments inside a parenthesis followin...

string nullString = null; string emptyString = ""; string whitespaceString = " "; string tabString = "\t"; string newlineString = "\n"; string nonEmptyString = "abc123"; bool result; result = String.IsNullOrEmpty(nullString); ...

From ES5.1 onwards, you can use the native method Array.prototype.filter to loop through an array and leave only entries that pass a given callback function. In the following example, our callback checks if the given value occurs in the array. If it does, it is a duplicate and will not be copied to...

var arr = [1, 2, 3, 4]; Method 1 Creates a new array and overwrites the existing array reference with a new one. arr = []; Care must be taken as this does not remove any items from the original array. The array may have been closed over when passed to a function. The array will remain in mem...

This query will return all COLUMNS and their associated TABLES for a given column name. It is designed to show you what tables (unknown) contain a specified column (known) SELECT c.name AS ColName, t.name AS TableName FROM sys.columns c JOIN sys.tables t ON c.object_id = t.o...

The easiest way to get started with Gremlin is to install the Gremlin Console. The Gremlin Console is a REPL that allows immediate feedback on the results of Gremlin traversals. As a prerequisite, Java 8 is required for the Gremlin Console to run. Ensure that it is installed prior to moving forward...

You can redirect the debug output to a text file by adding a TextWriterTraceListener to the Debug.Listeners collection. public static void Main(string[] args) { TextWriterTraceListener myWriter = new TextWriterTraceListener(@"debug.txt"); Debug.Listeners.Add(myWriter); Deb...

return http://www.example.com/skin/frontend/{interface}/{theme}/images/my-image.jpg

Mage::getSingleton('admin/session')->getUser();

Mage::helper('customer')->getCustomer(); or Mage::getSingleton('customer/session')->getCustomer();

If you want to display to your users meaningful errors instead of simple "sorry, something went wrong", Rails has a nice utility for the purpose. Open the file app/controllers/application_controller.rb and you should find something like this: class ApplicationController < ActionContro...

If you ever wanted to determine the html content to be printed on a page during run time then, rails has a very good solution for that. It has something called the content_for which allows us to pass a block to a rails view. Please check the below example, Declare content_for <div> <%=...

You can rollback and then migrate again using the redo command. This is basically a shortcut that combines rollback and migrate tasks. Run command: 5.0 rake db:migrate:redo 5.0 rails db:migrate:redo You can use the STEP parameter to go back more than one version. For example, to go ba...

<PROJECT_ROOT>\app\build.gradle is specific for app module. <PROJECT_ROOT>\build.gradle is a "Top-level build file" where you can add configuration options common to all sub-projects/modules. If you use another module in your project, as a local library you would have another...

You can define the signing configuration to sign the apk in the build.gradle file using these properties: storeFile : the keystore file storePassword: the keystore password keyAlias: a key alias name keyPassword: A key alias password In many case you may need to avoid this kind of info in ...

In Aurelia all HTML templates are defined inside of opening and closing <template></template> tags. All of your HTML and Aurelia specific logic goes inside of these template tags and cannot exist outside of them. <template> </template>

Looping over an iterable defined inside of your viewmodel or passed through as a bindable (if a Custom Attribute or Custom Element) can be done like so. An array of string values export class MyViewModel { myIterable = ['String 1', 'String 2', 'String 3', 'String 4']; } <template> ...