Regular expressions are a powerful tool for working with formal languages. They aren't useful, though, when working with languages that aren't formal, such as markup languages. A common mistake when working with RegExes is to attempt to use them to parse HTML and XML.Regex: A Double-Edged Sword
Yet, their power comes with significant risk. An incorrectly written regex can introduce vulnerabilities, leading to security breaches such as denial of service (DoS) attacks, data leakage, and unauthorized access.Today, regexes are widely supported in programming languages, text processing programs (particularly lexers), advanced text editors, and some other programs.
What are the disadvantages of regex : 4 Disadvantages of regex for control logic
They can be hard to understand and maintain, especially for complex or long patterns. They can also be prone to errors and bugs, such as typos, syntax errors, or unintended matches. Another disadvantage of regex is that they are not very efficient or scalable.
Is regex lazy or greedy
and the string to match is all HTML tags. Greedy search — will try to match the longest possible string. The above regex matches the whole string ( <h1>Hello World</h1> ) because by default Regular Expression uses the Greedy algorithm & hence it finds the longest match.
Why is regex inefficient : Regex is slow because it's more complex than it seems. Every expression needs to be parsed and compiled (yes, compiled).
Risk Factors
The Web is Regex-Based: In every layer of the WEB there are Regular Expressions, that might contain an Evil Regex. An attacker can hang a WEB-browser (on a computer or potentially also on a mobile device), hang a Web Application Firewall (WAF), attack a database, and even stack a vulnerable WEB server. contains(String) is much faster than explicitly using Regex .
Do software engineers use regex
We use regular expressions frequently in our applications (ecommerce systems, microservices, etc.), be it for validation, search and replace, or anything else where useful.Their advantages are that they are concise, they run very quickly, they can be ported across languages (they are definitely not just a Python thing!), and they are very powerful. The disadvantage is that they are confusing and take some getting used to!Excessive backtracking is the main cause of performance problems with regex matching. When the engine backtracks exponentially, time to finish the match grows drastically with the length of the string. In most cases, it performs pattern matching rapidly and efficiently. However, in some cases, the regular expression engine can appear to be slow. In extreme cases, it can even appear to stop responding as it processes a relatively small input over the course of hours or even days.
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Antwort Should I avoid using regex? Weitere Antworten – Should we avoid regex
Regular expressions are a powerful tool for working with formal languages. They aren't useful, though, when working with languages that aren't formal, such as markup languages. A common mistake when working with RegExes is to attempt to use them to parse HTML and XML.Regex: A Double-Edged Sword
Yet, their power comes with significant risk. An incorrectly written regex can introduce vulnerabilities, leading to security breaches such as denial of service (DoS) attacks, data leakage, and unauthorized access.Today, regexes are widely supported in programming languages, text processing programs (particularly lexers), advanced text editors, and some other programs.
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What are the disadvantages of regex : 4 Disadvantages of regex for control logic
They can be hard to understand and maintain, especially for complex or long patterns. They can also be prone to errors and bugs, such as typos, syntax errors, or unintended matches. Another disadvantage of regex is that they are not very efficient or scalable.
Is regex lazy or greedy
and the string to match is all HTML tags. Greedy search — will try to match the longest possible string. The above regex matches the whole string ( <h1>Hello World</h1> ) because by default Regular Expression uses the Greedy algorithm & hence it finds the longest match.
Why is regex inefficient : Regex is slow because it's more complex than it seems. Every expression needs to be parsed and compiled (yes, compiled).
Risk Factors
The Web is Regex-Based: In every layer of the WEB there are Regular Expressions, that might contain an Evil Regex. An attacker can hang a WEB-browser (on a computer or potentially also on a mobile device), hang a Web Application Firewall (WAF), attack a database, and even stack a vulnerable WEB server.
![]()
contains(String) is much faster than explicitly using Regex .
Do software engineers use regex
We use regular expressions frequently in our applications (ecommerce systems, microservices, etc.), be it for validation, search and replace, or anything else where useful.Their advantages are that they are concise, they run very quickly, they can be ported across languages (they are definitely not just a Python thing!), and they are very powerful. The disadvantage is that they are confusing and take some getting used to!Excessive backtracking is the main cause of performance problems with regex matching. When the engine backtracks exponentially, time to finish the match grows drastically with the length of the string.
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In most cases, it performs pattern matching rapidly and efficiently. However, in some cases, the regular expression engine can appear to be slow. In extreme cases, it can even appear to stop responding as it processes a relatively small input over the course of hours or even days.