What is an IndexOutOfRangeException / ArgumentOutOfRangeException and how do I fix it?

To easily understand the problem, imagine we wrote this code: static void Main(string[] args) { string[] test = new string[3]; test[0]= “hello1”; test[1]= “hello2”; test[2]= “hello3”; for (int i = 0; i <= 3; i++) { Console.WriteLine(test[i].ToString()); } } Result will be: hello1 hello2 hello3 Unhandled Exception: System.IndexOutOfRangeException: Index was outside the bounds of the […]

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What is a NullReferenceException, and how do I fix it?

What is the cause? Bottom Line You are trying to use something that is null (or Nothing in VB.NET). This means you either set it to null, or you never set it to anything at all. Like anything else, null gets passed around. If it is null in method “A”, it could be that method “B” passed a null to method “A”. null can have different meanings: Object variables […]

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RegEx match open tags except XHTML self-contained tags

While arbitrary HTML with only a regex is impossible, it’s sometimes appropriate to use them for parsing a limited, known set of HTML. If you have a small set of HTML pages that you want to scrape data from and then stuff into a database, regexes might work fine. For example, I recently wanted to get the names, parties, […]

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How can I prevent SQL injection in PHP?

The correct way to avoid SQL injection attacks, no matter which database you use, is to separate the data from SQL, so that data stays data and will never be interpreted as commands by the SQL parser. It is possible to create SQL statement with correctly formatted data parts, but if you don’t fully understand the details, you should always use prepared statements […]

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(ANSWER) How to make a great R reproducible example

Basically a minimal reproducible example (MRE) should enable others to exactly reproduce your issue on their machines. A MRE consists of the following items: a minimal dataset, necessary to demonstrate the problem the minimal runnable code necessary to reproduce the error, which can be run on the given dataset all necessary information on the used packages, the R version, and the OS it is run on. […]

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How can I use CSS Pseudo-elements styling inside React JSX to pass variables?

You can use from styled-components: import React from ‘react’; import styled from ‘styled-components’; const Div = styled.div` &::before{ position: absolute; content: “”; background: #283593; height: 18px; width: 18px; top: 2.5rem; right: -0.7rem; z-index: -1; transform: rotate(45deg); } &::after{ position: absolute; content: ${props => props.name}; top: 11px; right: -14px; padding: 0.5rem; width: 11rem; background: #3949ab; color: […]

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