Question

I thought I was doing \[/b\]

but the machine disagrees.

Answer 1

How do you match [ ] with regex?

\[ \] should do just fine. At least in the Java regular expression engine.

System.out.println("[ ]".matches("\\[ \\]"));   // prints true

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Not sure where you get the /b from. Perhaps you’re after a “blank” character. The most common expression for whitespace characters is \s. I.e., you could do \[\s\].

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(Matching balanced [ ] is another story though. A task which regular expression are not very well suited for.)