filtering - How to define patterns to filter lists of replacement rules?

I have a list of replacement rules like

list˘of˘replacement˘rules = {a -> 1, b -> 2, c -> 3}

and I want to filter all the elements where ‘b’ is replaced by using Cases[] and a search pattern.
The following code does not work:

Cases[list˘of˘replacement˘rules, b -> _]

The result is {}.
How should the pattern be defined in order to get the result {b->2}?

Answer

rules = {a -> 1, b -> 2, c -> 3};


FilterRules[rules, b]
(* {b -> 2} )*

Cases[{a -> 1, b -> 2, c -> 3}, PatternSequence[b -> _]]
(* {b -> 2} )*

Comments

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