![]() ✽ Matthew Barnett's regex module for Python. ✽ PCRE flavor, when programming in PHP and for Apache. Here are some of the flavors of regex I frequently use, and their context: It may very well be that the flavor of regex you use does not coincide with anything I use, though that would be bad luck indeed. That is indeed the most common implementation in modern languages. When you can choose between NFA or DFA, NFA is usually the fastest. ✽ text-directed (or DFA, which stands for Deterministic Finite Automaton) ✽ regex-directed (or NFA, which stands for Nondeterministic Finite Automaton) The engines behind these flavors fall into two main groups: ![]() You see, everyone who implements a regex engine does so a little differently from anyone else. In the window of RegexBuddy, a fabulous little regex tool I can't work without (more about it later, free trial download here), I can choose between contexts such as C#, Python, Java, PHP, Perl, Ruby, JavaScript, Scala, and many more. More importantly, regex also comes in many flavors. If I've missed an important category, please shoot me a comment at the bottom of the page.Īs I'm sure you're aware, regular expressions are known by different names: regex or the increasingly infrequent regexp, and their plural regexes, regexps or regexen. Helping you while away the tedious afternoon office hours by exchanging regex challenges with your colleagues. Telling Apache how to behave with certain IP addresses, urls or browsers, in htaccess for instance.ĩ. Searching from the command line using Perl one-liners and utilities such as grep, sed and awk.Ĩ. ![]() If you haven't seen it yet, you really owe it to yourself to take a tour of Directory Opus features or install the nag-free, fully functional 60-day trial.Ħ. Opus is a unique tool-in my view the most important productivity tool a Windows user can have! Why such an extravagant-sounding statement? Because for most users, an enormous amount of computer time disappears unnoticed in the black hole of file operations-looking for, moving and renaming files. I should hasten up to add that there really isn't anything "like" Directory Opus. Renaming a hundred files at a time in an advanced file manager such as Directory Opus or a renamer such as PFrank (Win) or A Better Finder Rename (OSX). For advanced search and replace when using creativity software such as Adobe Indesign.ĥ. Searching and replacing across pages of code when using in an IDE such as Visual Studio, Komodo IDE or even Dreamweaver's crippled ECMAScript flavor.Ĥ. I use regex to rename files, to search in files, to make large-scale substitutions in code, in code (PHP), with databases (mySQL) and to direct my web server (Apache).ģ. In the result window, the results change instantaneously as you tweak the expression, much as in RegexBuddy. It does one job, and does it brilliantly: searching for and replacing text in a file, or many files at once. ![]() Still, a ten-year-old PCRE is a lot better than JavaScript.įor replacement in text files, I love ABA Replace. This means that a lot of juicy features are missing. What they don't say is that the PCRE version they use is 4.0 from 17 February 2003-or so it appears to me, as it supports from 4.0 but not \X from 5.0. On OSX, the free TextWrangler its big brother BBEdit both claim to use PCRE. The free Notepad used to be deficient in the regex department, but since version 6, it has been using the excellent PCRE engine-though the interface is still clunky. If you want to try EditPad Pro, download the free trial. Among text editors, EditPad Pro is in a league of its own because its regex engine was programmed by the creator of RegexBuddy. Searching (and possibly replacing) text in files when using an advanced text editor such as EditPad Pro and Notepad on Windows (or TextWrangler / BBEdit on OSX), a standalone replace tool such as ABA Replace, or good old grep (the linked page has the best command-line grep for Windows).Ī few words about the tools just mentioned. Grabbing text in files or validating text input when programming in languages such as C, Java or PHP.Ģ. Here are some of the thing regular expressions can help you do.ġ. As a result, the content is not as polished as most of my other pages. Finally, we'll study some examples of regex patterns in contexts such as:ĭisclaimer: I haven't edited this page in a while. Then we'll have a quick look at some regex flavors you may run into. On this page, we'll first look at a number of contexts and programs where you may find regex. Once you learn it, you discover it comes in handy in many places where you hadn't planned to use it. I have not yet had time to revise this page, so please be aware that it is not up the same standard as most pages in the tutorial. August 2014: Lately I've added many new regex pages and been making major overhauls to old ones.
0 Comments
Leave a Reply. |