I have this string -: @Harry @Harry are great twins with @Harry
I would want to match @Harry in the above string. But on one condition -:
@Harry should be preceeded by either nothing or a white space character only, same goes for succession too.
So here 3 matches must be found. Currently i am doing this, but in vain -: (\s|^$)\@Harry(\s|^$).
^$ means an empty string.
[\s means more than a whitespace (source) so you should just use a whitespace :)] <= Unnecessary
So, without taking the whitespace as part of the match:
"/(?<=^|\s)@Harry(?=\s|$)/"
Edit:
Source for the lookarounds.
Also, if you want to match the whitespaces, remove those lookarounds.