Regex match character with negative lookbehind of two chars

Question

I want to split a string using the character "/", but the split should only occur if there is no "\" in front of it.

String:

/10/102-\/ABC083.013/11/201201/20/83/30/463098194/32/7.7/40/0:20

Regex:

\/*(?<!\\)[^\/]*\/*(?<!\\)[^\/]*

Expected result:

/10/102-\/ABC083.013
/11/201201
/20/83
/30/463098194
/32/7.7
/40/0:20

But with my regex I get:

/10/102-\
/ABC083.013/11
/201201/20
/83/30
/463098194/32
/7.7/40
/0:20

online regex example

The issue is on the first group "/10/102-\/ABC083.013", it does not recognize the string "\/" to the first group. I don't know how to optimize/change my regex so that it recognizes the first group correctly.

Answer 1

Another option is to match 2 times a forward slash, and only match a / when preceded by a \

(?:\/(?:[^\/]|(?<=\\)\/)+){2}

Explanation

• (?: Non capture group
  • \/ Match /
  • (?: Non capture group
    • [^\/] Match any char other than /
    • | Or
    • (?<=\\)\/ Match / not preceded by \
  • )+ Close group and repeat 1+ times to match at least 1 char other than /
• ){2} Close group and repeat 2 times

Regex demo

---

Or a slightly more efficient unrolled version

(?:\/[^\\\/]+(?:\\.[^\\\/]*)*){2}

Explanation

• (?: Non capture group
  • \/[^\\\/]+ Match / followed by 1+ times any char other than \ and /
  • (?: Non capture group
    • \\.[^\\\/]* Match an escaped char followed by 0+ times any char other than \ and /
  • )* Close the group and repeat 0+ times (in case there are no occurrences of an escaped char)
• ){2} Close group and repeat 2 times

Regex demo