=< doesn't look like any operator I've ever met, but still, assuming you want to match =, !=, <, >, <= and >=, then note that ther operands involving less than and greater than are different, in that they may be followed by an = (equals), accounting for two more operators for free. That gives us

[<>]=?

That leaves = and !=. This is just equals, maybe preceded by an excla. This gives

!?=

Now all the operators have been accounted for. Putting them together in a capturing group with an alternation gives:

([<>]=?|!?=)

Dividing the atoms you want to match into different groups is usually the best way of coming up with an expression that matches all of them. Also, you want to consider patterns that share a similar beginning, since this way you'll end up with a regular expression that doesn't have to backtrack.

If you really meant to match =<, then with the above approach you should be able to come up with something that works. Look at all the operators that start with an =, and then the remaining operators that don't.