What is the difference between ==~ and != in Groovy?

In Java, != is “not equal to” and ~ is "bitwise NOT". You would actually be doing variable == ~6.

In Groovy, the ==~ operator is "Regex match". Examples would be:

1. "1234" ==~ /\d+/ -> evaluates to true
2. "nonumbers" ==~ /\d+/ -> evaluates to false

In groovy, the ==~ operator (aka the "match" operator) is used for regular expression matching. != is just a plain old regular "not equals". So these are very different.

cf. http://groovy-lang.org/operators.html

In Groovy you also have to be aware that in addition to ==~, alias "Match operator", there is also =~, alias "Find Operator" and ~, alias "Pattern operator".

All are explained here.

==~ result type: Boolean/boolean (there are no primitives in Groovy, all is not what it seems!)

=~ result type: java.util.regex.Matcher

~ result type: java.util.regex.Pattern

I presume the Groovy interpreter/compiler can distinguish between ~ used as a Pattern operator and ~ used as a bitwise NOT (i.e. its use in Java) through context: the former will always be followed by a pattern, which will always be bracketed in delimiters, usually /.