Category: regex
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Yet another website re-design
This is the third post about redesigning my website now. I did a major re-write and re-design in 2010, and then again in 2021. I have been thinking about redesigning again for over a year, after the release of WordPress 5.9, which added full-site editing (FSE) also known as the “Site Editor”. This takes the…
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UNIX tip of the day – grep -P is slow
Unless you really need some advanced regular expressions only supported by PCRE, using POSIX regular expressions with grep is usually an order of magnitude faster – that’s because the default engine with grep uses finite automata, as opposed to a backtracking algorithm which PCRE uses ( the main featuress you gain from the backtracking algorithm…
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Unicode block names in regular expressions
Frequently, I find myself wanting to do some simple language detection. For Chinese, Japanese, and Korean, this can easily be done by looking at the types of characters in some text. The simplest and most robust way to do this is to use Unicode block names. It is very simple to write a regular expression…
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Java anchored regex
I just discovered this today when doing some regex in Java. When I first started doing regex in Java, I was surprised to learn that Java seems to treat all regular expressions as anchored. That is, if you have a string foobar and search for “foo” it will not match. This is different than grep,…