正则表达式：模式包含0个或多个特殊字符

Question

this syntax returns an array with a word key.

(?<item>\w+)  

ex. $array['item']

I want the return value in this form but I want to search for a word that may or may not contain parentheses (with values in between).

"hello"
or
"hello(some text and line breaks)"

What is the syntax for this?

Answer 1

\w+(?:\([^)]*\))?

will match words that can optionally be directly followed by a parenthesized text. Nested parentheses are not allowed.

\w+    # Match alnum characters
(?:    # Match the following (non-capturing) group:
 \(    # literal (
 [^)]* # any number of characters except )
 \)    # literal )
)?     # End of group; make it optional

Answer 2

hello(\(\))?

或如果您的正则表达式引擎默认括号为普通字符

hello\(()\)?