Regex

Problem

How to find if string has alphanumeric characters?

Solution

Pattern p = Pattern.compile("[^0-9a-z]", Pattern.CASE_INSENSITIVE);

boolean b = p.matcher("My String").find();

Regex Lookup table

^	Matches the starting position within the string. In line-based tools, it matches the starting position of any line.
*	Matches the preceding element zero or more times. For example, ab*c matches "ac", "abc", "abbbc", etc. [xyz]* matches "", "x", "y", "z", "zx", "zyx", "xyzzy", and so on. (ab)* matches "", "ab", "abab", "ababab", and so on.
.	Matches any single character
?	Matches the preceding element zero or one time. For example, ab?c matches only "ac" or "abc".
+	Matches the preceding element one or more times. For example, ab+c matches "abc", "abbc", "abbbc", and so on, but not "ac".
|	The choice (also known as alternation or set union) operator matches either the expression before or the expression after the operator. For example,abc|def matches "abc" or "def".
{m,n}	Matches the preceding element at least m and not more than n times. For example, a{3,5} matches only "aaa", "aaaa", and "aaaaa".
[ ]	A bracket expression. Matches a single character that is contained within the brackets. For example, [abc] matches "a", "b", or "c".