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To build a Rails application that will be an API server, you can start with a more limited subset of Rails in Rails 5. To generate a new Rails API app: rails new my_api --api What --api does is to remove functionality that is not needed when building an API. This includes sessions, cookies, ass...

Sometimes you may need to validate record only under certain conditions. class User < ApplicationRecord validates :name, presence: true, if: :admin? def admin? conditional here that returns boolean value end end If you conditional is really small, you can use a Proc: class ...

In PHP, there are two versions of logical AND and OR operators. OperatorTrue if$a and $bBoth $a and $b are true$a && $bBoth $a and $b are true$a or $bEither $a or $b is true$a || $bEither $a or $b is true Note that the && and || opererators have higher precedence than and and or. S...

In cryptography, encryption is the process of encoding messages or information in such a way that only authorized parties can access it. Source: Encryption - Wikipedia

Imagine that we have a separate Google spreadsheet, and we need to get the B2 cell value to cell D5 on your current sheet. function copyValueandPaste() { var source = SpreadsheetApp.openById('spread sheet id is here'); //Separate spreadsheet book var sourcesheet = source.getSheetByName...

As with docopt, with [docopt_dispatch] you craft your --help in the __doc__ variable of your entry-point module. There, you call dispatch with the doc string as argument, so it can run the parser over it. That being done, instead of handling manually the arguments (which usually ends up in a high c...

Functions that are O(n) increase the number of operations linearly, as the input gets very large. A simple example of a function that is O(n) would be the linear search algorithm, which runs once for the size of the input. The following pseudo-code would be O(n), because it will always be bounded ...

We can add Kendo-UI grid in HTML5/Javascript, ASP.NET MVC, JSP and PHP project/application. Please follow below steps to add kendo-UI grid in HTML5 page. Create empty html5 page. Include kendo.common.min.css and kendo.default.min.css. Add a link tag within the head tag. Kendo-UI li...

Consider the following naive method for adding two positive numbers using recursion: public static int add(int a, int b) { if (a == 0) { return b; } else { return add(a - 1, b + 1); // TAIL CALL } } This is algorithmically correct, but it has a major problem. ...

Manually open and close a file. # Using new method f = File.new("test.txt", "r") # reading f = File.new("test.txt", "w") # writing f = File.new("test.txt", "a") # appending # Using open method f = open("test.txt", "r&...

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For immutable elements (e.g. None, string literals etc.): my_list = [None] * 10 my_list = ['test'] * 10 For mutable elements, the same construct will result in all elements of the list referring to the same object, for example, for a set: >>> my_list=[{1}] * 10 >>> print(my_...

General syntax: DATEADD (datepart , number , datetime_expr) To add a time measure, the number must be positive. To subtract a time measure, the number must be negative. Examples DECLARE @now DATETIME2 = GETDATE(); SELECT @now; --2016-07-21 14:39:46.4170000 SELECT DAT...

General syntax: DATEDIFF (datepart, datetime_expr1, datetime_expr2) It will return a positive number if datetime_expr is in the past relative to datetime_expr2, and a negative number otherwise. Examples DECLARE @now DATETIME2 = GETDATE(); DECLARE @oneYearAgo DATETIME2 = DATEADD(YEAR, -1, @now...

Using the DATEADD and DATEDIFF functions, it's possible to return the last date of a month. SELECT DATEADD(d, -1, DATEADD(m, DATEDIFF(m, 0, '2016-09-23') + 1, 0)) -- 2016-09-30 00:00:00.000 SQL Server 2012 The EOMONTH function provides a more concise way to return the last date of a month, and...

Sometimes when destructuring maps, you would like to bind the destructured values to their respective key name. Depending on the granularity of the data structure, using the standard destructuring scheme may be a little bit verbose. Let's say, we have a map based record like so : (def john {:lastn...

One approach that is employed often is to use bootstrap's gridded framework in order to define the area that the chart will exist in. Using this in conjunction with clientWidth variable and the window.onresize event, it is very easy to create responsive d3 SVGs. Let's first create a row and a colum...

A CSS rule consists of a selector (e.g. h1) and declaration block ({}). h1 {}

Some properties can take multiple values, collectively known as a property list. /* Two values in this property list */ span { text-shadow: yellow 0 0 3px, green 4px 4px 10px; } /* Alternate Formatting */ span { text-shadow: yellow 0 0 3px, green 4px 4px 10px; } ...