{n,} is a greedy quantifier whose lazy equivalent is {n,}?. [a-zA-Z0-9]+ Matches at least one alpha-numeric character. However, only the initial portion of this substring (up to the space and the fifth pair of zeros) matches the regular expression pattern. Typically used to validate complex passwords or usernames. The * quantifier matches the preceding element zero or more times. We and our partners use data for Personalised ads and content, ad and content measurement, audience insights and product development. character to a quantifier makes it lazy. posts. Wall shelves, hooks, other wall-mounted things, without drilling? To use regex in order to search for a particular phone number we can use the following expression. Many a time we want to check if the string contains any upper case character, lower case character, a special character from the provided list, or a digit between 0 to 9. Ordinarily, quantifiers are greedy. For example, the regular expression \b\d{2,}\b\D+ tries to match a word boundary followed by at least two digits followed by a word boundary and a non-digit character. Are the models of infinitesimal analysis (philosophically) circular? xy*z could correspond to "xz", "xyz", "xyyz", etc. The reason the second string did not match with the pattern even though it had both upper and lower case characters is that the regex engine consumes characters while matching them with the pattern. As you can see from the output, it only matches when all of the three character classes are present in the string. If you would like to change your settings or withdraw consent at any time, the link to do so is in our privacy policy accessible from our home page.. To learn more, see our tips on writing great answers. How do I reference the input of an HTML