Remove square brackets that don't have spaces between them

Question

I'm trying to remove square brackets that don't have spaces between them, but keep square brackets that do. For example:

• Match these brackets and remove them: [ please ]
• Don't match these brackets and remove them: [ help me ]

Note: I want to match just the brackets, not the content.

I think that I need to use look ahead, eg \\\\[(?!= ) . However, this only looks ahead to the next character, whereas I want to check that all characters between the square brackets are not spaces. What to do in this situation?

Answer 1

The new version of stringr may be of use to you, it has a nice widget for testing out regex matching.

stringr::str_view_all(c("[please]", "[help me]"), "(\\[)\\S*(\\])")

matches [ , then any number of non-space characters, then ] , with the [ and ] as capture groups. I'm not sure what you want to do with them.

Update: To remove brackets, you actually want to capture what's inside and then substitute with it.

stringr::str_replace_all(c("[please]", "[help me]"), "\\[(\\S*)\\]", "\\1")
#> [1] "please"    "[help me]"

(capture any all-non-space characters between brackets, and substitute the entire string for the capture where found)