Green’s Dictionary of Slang

in one’s opinion, as far as one is concerned, e.g. by me, by you, by us.

1923		T.A. Dorgan in Zwilling TAD Lex. (1993) 23: By chiminey everytink is wrong by me today.
1936		(con. 1920s) Dos Passos Big Money in USA (1966) 901: It’s all right by me, boss.
1947		G. Kersh Prelude to a Certain Midnight Bk I Ch. v: By him a pound is already important.
1954		Mad mag. Dec. 3: It may be quaint by you! ... it may be delightful by you! ... It may be Wonderland by you! ... By me it’s only one thing ... Scary!
1963		in T.I. Rubin Sweet Daddy 79: By me you’re okay.
1975		E. Torres Carlito’s Way 94: I [...] got the word that everything was okay by Rocco.
1986		L. Heinemann Paco’s Story (1987) 156: ‘I ain’t putting out for you, buster, not so much as a handshake!’ ‘Okay by me, girlie.’.
1998		P. McCabe Breakfast on Pluto 85: Long as they’s ’avin themselves a good time, that’s awright by me!
2000		G. Pelecanos Shame the Devil 60: It was okay by Walters for those kids to think whatever they wanted.