Matching an empty string with regex

Question

I\'ve seen posts here on stackoverflow that say that the regex ^$ will match an empty string... So it made me think... why not something like this: ^\\s+$

Answer 1

As others said, you probably mean ^\s*$, not ^\s+$, because ^\s+$ will fail to match the empty string, .

Whether ^\s*$ matches an empty string depends on your definition of "empty". Like ^$, it will match the completely empty string . Unlike ^$, it will also match a string consistening of only whitespace characters like spaces and tabs, such as    . Which is the "right" definition of "empty" depends on the situation.