java - How to test if a String contains both letter and number

Question

I need a regex which will satisfy both conditions.

It should give me true only when a String contains both A-Z and 0-9.

Here\'s what I\'ve tried:

Answer 1

Here is the regex for you

Basics:

Match in the current line of string: .

Match 0 or any amount of any characters: *

Match anything in the current line: .*

Match any character in the set (range) of characters: [start-end]

Match one of the regex from a group: (regex1|regex2|regex3)

Note that the start and end comes from ASCII order and the start must be before end. For example you can do [0-Z], but not [Z-0]. Here is the ASCII chart for your reference

Check the string against regex

Simply call yourString.matches(theRegexAsString)

Check if string contains letters:

Check if there is a letter: yourString.matches(".*[a-zA-Z].*")

Check if there is a lower cased letter: yourString.matches(".*[a-z].*")

Check if there is a upper cased letter: yourString.matches(".*[A-Z].*")

Check if string contains numbers:

yourString.matches(".*[0-9].*")

Check if string contains both number and letter:

The simplest way is to match twice with letters and numbers

yourString.matches(".*[a-zA-Z].*") && yourString.matches(".*[0-9].*")

If you prefer to match everything all together, the regex will be something like: Match a string which at someplace has a character and then there is a number afterwards in any position, or the other way around. So your regex will be:

yourString.matches(".*([a-zA-Z].*[0-9]|[0-9].*[a-zA-Z]).*")

Extra regex for your reference:

Check if the string stars with letter

yourString.matches("[a-zA-Z].*")

Check if the string ends with number

yourString.matches(".*[0-9]")