Until now, all the constraints we have been putting on our patterns had to do with characters that could or couldn't be displayed, but Regex provides a number of positional constraints, which allow you to filter out some false positives.
The first such set is the start and end of string matchers. Using the (
^) caret character to match the start of a string and the (
$) dollar sign to match the end, we can force a pattern to be positioned in these locations, for example, you can add the dollar sign at the end of a word to make sure that it is the last thing in the provided string. In the next example, I used the
/^word|word$/g pattern to match an occurrence of
word, which either starts or ends a string. The following image exemplifies the match of the regular expression when given a Text input:
Using both the start and end character together assure that your pattern is the only thing in the string. For example if you have a