
Between Markers

You are given a string and two markers (the initial and final). You have to find a substring enclosed between these two markers. But there are a few important conditions:
- The initial and final markers are always different.
- If there is no initial marker, then the first character should be considered the beginning of a string.
- If there is no final marker, then the last character should be considered the ending of a string.
- If the initial and final markers are missing then simply return the whole string.
- If the final marker comes before the initial marker, then return an empty string.
Input: Three arguments. All of them are strings. The second and third arguments are the initial and final markers.
Output: A string.
Example:
assert between_markers("What is >apple<", ">", "<") == "apple" assert ( between_markers("<head><title>My new site</title></head>", "<title>", "</title>") == "My new site" ) assert between_markers("No[/b] hi", "[b]", "[/b]") == "No" assert between_markers("No [b]hi", "[b]", "[/b]") == "hi"
How it is used: for parsing texts
Precondition: can't be more than one final marker and can't be more than one initial. Marker can't be an empty string