Regex match for beginning of multiple words in string

Question

In Javascript i want to be able to match strings that begin with a certain phrase. However, I want it to be able to match the start of any word in the phrase, not just the beginning of the phrase.

For example:

Phrase: "This is the best"

Need to Match: "th"

Result: Matches Th and th

EDIT: \b works great however it proposes another issue:

It will also match characters after foreign ones. For example if my string is "Männ", and i search for "n", it will match the n after Mä...Any ideas?

Answer 1

Use this:

string.match(/^th|\sth/gi);

Examples:

'is this is a string'.match(/^th|\sth/gi);


'the string: This is a string'.match(/^th|\sth/gi);

Results:

["th", " Th"]

["th"]

Answer 2

var matches = "This is the best".match(/\bth/ig);

returns:

["Th", "th"]

The regular expression means: Match "th" ignoring case and globally (meaning, don't stop at just one match) if "th" is the first word in the string or if "th" is preceded by a space character.

Answer 3

Use the g flag in the regex. It stands for "global", I think, and it searches for all matches instead of only the first one.

You should also use the i flag for case-insensitive matching.

You add flags to the end of the regex (/<regex>/<flags>) or as a second parameter to new RegExp(pattern, flags)

For instance:

var matches = "This is the best".match(/\bth/gi);

or, using RegExp objects:

var re = new RegExp("\\bth", "gi");
var matches = re.exec("This is the best");

EDIT: Use \b in the regex to match the boundary of a word. Note that it does not really match any specific character, but the beginning or end of a word or the string.