C# Regex to split using space but exclude text between [: and :] special characters

Question

I need two C# Regular expressions to split using space but exclude text between [: and :] special characters.

1. Need regex to split text but exclude text between [: and :] special characters.
2. Need regex to split text but exclude text between [: and :] and also the text between [ and ] special characters.

Example: 1st Case:

string input1 = "one [two two] three [:four four:] five six [seven seven:] [:eight eight]";

output:

one
[two
two]
three
[:four four:]
five
six
[seven
seven:]
[:eight
eight]

Example: 2nd Case:

output:

one
[two two]
three
[:four four:]
five
six
[seven
seven:]
[:eight
eight]

I tried this but not working, producing below output

string input1 = "one [two two] three [:four four:] five six [seven seven:] [:eight eight]";
var parts1 = Regex.Matches(input1,  @"[[::]].+?[\[::]]|[^ ]+").Cast<Match>()
                        .Select(m => m.Value)
                        .ToArray();

one
[two two] three [:four four:]
five
six
[seven seven:]
[:eight
eight]

Answer 1

You can use

var pattern = @"\[:[^][]*:]|\[(?!:)[^][]*(?<!:)]|\S+";
var results = Regex.Matches(text, pattern).Cast<Match>().Select(x => x.Value);

See the regex demo.

Details:

• \[: - [: string
• [^][]* - zero or more chars other than [ and ]
• :]
• | - or
• \[ - a [ char
• (?!:) - immediately on the right, there should be no :
• [^][]* - zero or more chars other than [ and ]
• (?<!:)] - a ] char that has no : right before it
• | - or
• \S+ - one or more non-whitespace chars.