How to make an entire word optional in a regular expression?

php editor Banana will introduce to you how to make the entire word optional in a regular expression in this article. Regular expressions are powerful text matching tools that can be used to find, replace, and validate strings. Sometimes, we want a certain word to be optional when matching, that is, the word can appear in the string, but it also does not need to appear. With some simple techniques, we can implement this function in regular expressions, making matching more flexible and comprehensive. Next, let’s take a look at the specific methods!

Question content

It would be great if this could be achieved using the current regex format.

Regular expression:

\b([a][\W_]*?)+([p][\W_]*?)+([p][\W_]*?)+([l][\W_]*?)+([e][\W_]*?)+(([a][\W_]*?)+([n][\W_]*?)+([d][\W_]*?))?([l][\W_]*?)+([e][\W_]*?)+([m][\W_]*?)+([o][\W_]*?)+([n][\W_]*?)+\b

Regular Expressions 101:

https://regex101.com/r/wte6gg/2

Solution

The following expression needs to start with "apple", and then can be followed by "lemon" and "and ”, if both follow, you need to follow the order of “and Lemon” Does this help?

\b(Apple)( ?和)?( ?Lemon)?\b

//m.sbmmt.com/link/11eba2991cc62daa4a85be5c0cfdae97

edit

With your format, the following should work:

\b([a][\W_]*?) ([p][\W_]*?) ([p][\W_]*?) ([l][\W_] * ?) ([e][\W_]*?) (([\W_]*)([a][\W_]*?) ([n][\W_]*?) ([ d][\W_ ]*?) )?(([\W_]*)([l][\W_]*?) ([e][\W_]*?) ([m][\ W_]*?) ([o ][\W_]*?) ([n][\W_]*?) )?\b

//m.sbmmt.com/link/00693ceec3aa42db186efa62ed8917d2

If this is what you are looking for, please mark it as the answer.

The above is the detailed content of How to make an entire word optional in a regular expression?. For more information, please follow other related articles on the PHP Chinese website!