The rule correctly matches all test input data in any order and continues to work for missing fields. Line #4: pizza:ham and pineapple, drink:lime and lemonade ✅ Line #1: pizza:ham and pineapple, name:james buchanan and drink:lime and lemonade ✅ Here it is-a regular expression for extracting name-value pairs, separated by the = sign: Maybe you arrived here via Google and just want to copy and paste the rule to see if it works for you. To make things more complicated, what if you want to collect this data from many log lines, and the data isn’t always presented consistently? What regular expression will capture those values for you? However, you don’t want to extract the venue data or any other data in the log line. My favourite pizza=ham and pineapple drink=lime and lemonade venue=london name=james buchananįor this example data, let’s say you want to extract the pizza, drink, and name fields from the data. Some pairs might be present in all log lines, but some might not.Not all name-value pairs need to be collected.The pairs appear in the format: (attr=value).The log data contains multiple name-value pairs as well as other data.Here are the requirements for the real-world use case: New Relic has a powerful data parsing mechanism that lets you ingest raw log data and parse it into individual semantically meaningful columns. matcher. Now I want to extract this telephone number in another String. the phone number can be anywhere in the String like bla blaTELEPHONE NUMBERbla bla. This use case is based on a real-world requirement that was originally used to assist a customer with parsing their logs in New Relic. I am trying to extract phone number in java from the given String i.e. So let’s take a look at some regexes-on the way, you’ll hopefully learn to strengthen other regexes you work with.

Logs are a good example of when you need to have strong regular expressions because typically, logs are part of a wider system (ideally, you have logs for your entire stack), need to scale with your application, and are often inconsistent. REGEX: How to extract substring from string Ask Question Asked today. In this blog post, you'll learn how to put together a regex for an important use case: extracting name-value pairs from a log line, which is often an important part of managing your logs. However, reverse-engineering a complex regular expression isn’t much fun. Regex can seem complicated at first, but the system is logical and predictable once you can understand it. However, once you start using a regex as part of a wider system, at scale, or across unreliable data sets, the more you should ensure it is reliable, resilient, and performant. If your data is highly predictable, then optimizing a regex may be an unnecessary endeavor. Developing a good regular expression tends to be iterative, and the quality and reliability increase the more you feed it new, interesting data that includes edge cases.Ī regular expression that works is often good enough. Experience has taught me that regular expressions are the Swiss Army knife of the developer’s toolbox, and there's almost always a better regular expression for the job at hand.

Java regex extract number from string