Perl: Regex Quick question

[Alkaif]

If you try and substitute "is" for "was" in the string "This is silly" using

 s/is/was/ig

you won't get "This was silly", you'll get "Thwas was silly".



how would i correct this so it only subs is on its own with was.
so then the substituted value is "This was silly"?

[KevinR]

Use the \b anchor:

$_ = 'This is silly';
s/\bis\b/was/ig;
print;

You can look it up yourself in the perl documentation or online