Check if string contains single backslashes with regex

Question

I have tried to fix this for a long time, and i just can\'t do it.

It could be any string, but this is an example:

\"\\This string \\contains some\\ bac         


        

Answer 1

It seems you just want to check if a string matches a regex pattern partially, namely, if it contains a literal backslash not preceded nor followed with a backslash.

Use

(?

See the regex demo.

Sample Scala code:

val s = """"\This string\\ \contains some\ backslashes\""""
val rx = """(? true
  case _ => false
}
println(ismatch)

See the Scala online demo.

Note:

• """(? - this line declares a regex object and makes the pattern unanchored, so that no full string match is no longer required by the match block
• Inside match, we use case rx(_*) as there is no capturing group defined inside the pattern itself
• The pattern means: match a backslash (\\) that is not preceded with a backslash ((?) and is not followed with a backslash ((?!\\)).