50 home runs righty/lefty splits.

baseball-reference.com is the source but it does not have complete splits before about 1956. Therefore, the data for some is incomplete, including: Babe Ruth, Hack Wilson, Jimmie Foxx, Hank Greenberg, Ralph Kiner and Johnny Mize, so those players are omitted. Ruth and Mize batted left handed. Data for Willie Mays in 1955 is incomplete; Mays hit 51 home runs (HR) in 1955. His 1965 52 HR season is included.

Mickey Mantle popped up for both his 50 HR seasons but only for the circumstance of the switch hitter batting the opposite of how the pitcher throws. Non switch hitters have data for both the same and opposite handedness.

Massaging this data made me see obvious stuff that I had not noticed before. That's what's cool about this. After so much time there are still delightful discoveries hidden in plain sight.

Righty batters have hit 50 HR much more often. Only two lefties have hit 50 more than once. Babe Ruth and ... Do you know off the top of your head? Several righties have hit 50 multiple times starting with Foxx and ending with ...?

Below are sets of data by the four handedness combinations.

Bat Left, Pitch Left:

L	L	L	L	L	L	L	L	L	L	L
Player	Year	PA	AB	HR	HRtot	BA	OBP	SLG	OPS	BAbip
Chris Davis	2013	239	217	13	53	.235	.289	.475	.763	.284
Prince Fielder	2007	217	188	10	50	.261	.355	.479	.834	.275
David Ortiz	2006	241	205	18	54	.278	.373	.615	.988	.275
Ryan Howard	2006	225	197	16	58	.279	.364	.558	.923	.368
Jim Thome	2002	190	159	12	52	.245	.358	.497	.855	.287
Luis Gonzalez	2001	222	186	15	57	.312	.414	.624	1.038	.305
Barry Bonds	2001	189	141	17	73	.312	.487	.752	1.239	.300
Ken Griffey	1998	197	177	21	56	.299	.360	.701	1.061	.256
Ken Griffey	1997	217	196	14	56	.270	.332	.536	.868	.295
Brady Anderson	1996	224	187	13	50	.251	.355	.535	.889	.262
Roger Maris	1961	213	177	12	61	.232	.347	.475	.822	.210
L	L	L	L	L	L	L	L	L	L	L
Player	Year	PA	AB	HR	HRtot	BA	OBP	SLG	OPS	BAbip
min	min	189	141	10	50	.232	.289	.475	.763	.210
max	max	241	217	21	73	.312	.487	.752	1.239	.368
ave	ave	208	176	15	59	.273	.376	.600	.976	.265

Bonds fewest PA, AB, highest BA, OBP, SLG, OPS.
Davis: most AB, lowest OBP, SLG, OPS.
Griffey hit 21 of his 56 against lefties in one of his two 56 HR seasons.
Maris BAbip: .210 against lefties, .208 against righties.
*******************************

Bat Left, Pitch Right:

L	R	R	R	R	R	R	R	R	R	R
Player	Year	PA	AB	HR	HRtot	BA	OBP	SLG	OPS	BAbip
Chris Davis	2013	434	367	40	53	.316	.415	.728	1.142	.371
Prince Fielder	2007	464	385	40	50	.301	.414	.686	1.100	.288
David Ortiz	2006	445	353	36	54	.292	.434	.649	1.082	.268
Ryan Howard	2006	479	384	42	58	.331	.453	.711	1.164	.351
Jim Thome	2002	423	321	40	52	.333	.485	.766	1.251	.333
Luis Gonzalez	2001	506	423	42	57	.331	.435	.716	1.151	.294
Barry Bonds	2001	475	335	56	73	.334	.526	.910	1.437	.252
Ken Griffey	1998	523	456	35	56	.279	.367	.577	.944	.275
Ken Griffey	1997	487	412	42	56	.320	.405	.699	1.104	.289
Brady Anderson	1996	463	392	37	50	.319	.416	.686	1.103	.296
Roger Maris	1961	485	413	49	61	.286	.384	.683	1.066	.208
Mickey Mantle	1961	443	347	43	54	.291	.439	.692	1.131	.256
Mickey Mantle	1956	443	357	39	52	.342	.459	.737	1.196	.324
L	R	R	R	R	R	R	R	R	R	R
Player	Year	PA	AB	HR	HRtot	BA	OBP	SLG	OPS	BAbip
	min	423	321	35	50	.279	.367	.577	.944	.208
	max	523	456	56	73	.334	.526	.910	1.437	.371
	ave	474	387	43	57	.310	.428	.712	1.140	.271

Bonds: most HR (56), HRtot (73) highest BA, OBP, SLG, OPS
Griffey 1998: most PA, AB; fewest HR; lowest BA, OBP, SLG, OPS
Davis highest BAbip
Maris BAbip: .210 against lefties, .208 against righties.
*******************************

Bat Right, Pitch Right:

R	R	R	R	R	R	R	R	R	R	R
Player	Year	PA	AB	HR	HRtot	BA	OBP	SLG	OPS	BAbip
Jose Bautista	2010	554	461	46	54	.269	.388	.642	1.030	.240
Alex Rodriguez	2007	532	447	47	54	.327	.419	.680	1.099	.319
Andruw Jones	2005	526	461	42	51	.265	.346	.588	.934	.240
Alex Rodriguez	2002	544	465	49	57	.320	.412	.682	1.093	.301
Sammy Sosa	2001	574	484	51	64	.316	.406	.709	1.115	.319
Alex Rodriguez	2001	583	500	40	52	.324	.407	.626	1.033	.329
Sammy Sosa	2000	551	480	42	50	.313	.390	.644	1.034	.346
Sammy Sosa	1999	525	462	45	63	.279	.356	.608	.964	.283
Mark McGwire	1999	501	399	49	65	.286	.423	.694	1.117	.265
Greg Vaughn	1998	437	382	36	50	.275	.359	.623	.982	.262
Sammy Sosa	1998	521	479	54	66	.315	.361	.685	1.046	.310
Mark McGwire	1998	498	379	55	70	.314	.474	.794	1.268	.306
Mark McGwire	1997	508	423	46	58	.272	.380	.643	1.023	.260
Mark McGwire	1996	417	321	40	52	.293	.453	.713	1.167	.283
Albert Belle	1995	473	413	42	50	.324	.401	.729	1.130	.288
Cecil Fielder	1990	458	395	26	51	.235	.330	.473	.803	.280
George Foster	1977	427	386	32	52	.321	.375	.619	.994	.315
Willie Mays	1965	459	406	40	52	.320	.395	.670	1.065	.282
	R	R	R	R	R	R	R	R	R	R
Player	Year	PA	AB	HR	HRtot	BA	OBP	SLG	OPS	BAbip
min	min	417	321	26	50	.235	.330	.473	.803	.240
max	max	583	500	55	70	.327	.474	.794	1.268	.346
ave	ave	505	430	43	56	.298	.393	.657	1.050	.290

McGwire 1998: 55 HR against righties, 70, highest OBP, SLG, OPS
Sosa 54, 51 against righties.
Cecil Fielder fewest HR, only 26; lowest BA, OBP, SLG, OPS

*******************************

Bat Right, Pitch Left:

R	L	L	L	L	L	L	L	L	L	L
Player	Year	PA	AB	HR	HRtot	BA	OBP	SLG	OPS	BAbip
Jose Bautista	2010	129	108	8	54	.222	.333	.509	.843	.205
Alex Rodriguez	2007	176	136	7	54	.272	.432	.529	.961	.278
Andruw Jones	2005	146	125	9	51	.256	.349	.528	.877	.240
Alex Rodriguez	2002	181	159	8	57	.239	.331	.453	.784	.256
Sammy Sosa	2001	137	93	13	64	.387	.569	.882	1.451	.442
Alex Rodriguez	2001	149	132	12	52	.295	.369	.606	.975	.310
Sammy Sosa	2000	154	124	8	50	.347	.461	.597	1.058	.427
Sammy Sosa	1999	187	163	18	63	.313	.396	.712	1.107	.330
Mark McGwire	1999	160	122	16	65	.254	.425	.705	1.130	.200
Greg Vaughn	1998	224	191	14	50	.267	.371	.545	.915	.259
Sammy Sosa	1998	201	164	12	66	.287	.418	.537	.954	.357
Mark McGwire	1998	183	130	15	70	.254	.459	.631	1.090	.228
Mark McGwire	1997	149	117	12	58	.282	.436	.658	1.094	.323
Mark McGwire	1996	131	102	12	52	.373	.511	.784	1.296	.377
Albert Belle	1995	158	133	8	50	.293	.399	.571	.970	.307
Cecil Fielder	1990	215	178	25	51	.371	.479	.854	1.333	.387
George Foster	1977	262	229	20	52	.319	.393	.651	1.044	.308
Willie Mays	1965	179	152	12	52	.309	.404	.579	.983	.297
Mickey Mantle	1961	203	167	11	54	.371	.468	.677	1.145	.405
Mickey Mantle	1956	209	176	13	52	.375	.474	.642	1.116	.411
	L	L	L	L	L	L	L	L	L	L
Player	Year	PA	AB	HR	HRtot	BA	OBP	SLG	OPS	BAbip
min	min	129	93	7	50	.222	.331	.453	.784	.200
max	max	262	229	25	70	.387	.569	.882	1.451	.442
ave	ave	177	145	13	56	.304	.424	.633	1.056	.317

Sosa 2001 64 HR with only 93 AB against lefties; highest BA, OBP, SLG, OPS, BAbip.
Rodriguez 2007 only 7 of 54 against lefties.
Cecil Fielder (R) hit 25 of his 51 against lefties.
*******************************

Now let's put the min, max, ave sets adjacent for Bat/Pit:

Bat	Pit		PA	AB	HR	HRtot	BA	OBP	SLG	OPS	BAbip
L	L	min	189	141	10	50	.232	.289	.475	.763	.210
L	R	min	423	321	35	50	.279	.367	.577	.944	.208
R	R	min	417	321	26	50	.235	.330	.473	.803	.240
R	L	min	129	93	7	50	.222	.331	.453	.784	.200
Bat	Pit		PA	AB	HR	HRtot	BA	OBP	SLG	OPS	BAbip
L	L	max	241	217	21	73	.312	.487	.752	1.239	.368
L	R	max	523	456	56	73	.334	.526	.910	1.437	.371
R	R	max	583	500	55	70	.327	.474	.794	1.268	.346
R	L	max	262	229	25	70	.387	.569	.882	1.451	.442
Bat	Pit		PA	AB	HR	HRtot	BA	OBP	SLG	OPS	BAbip
L	L	ave	208	176	15	59	.273	.376	.600	.976	.265
L	R	ave	474	387	43	57	.310	.428	.712	1.140	.271
R	R	ave	505	430	43	56	.298	.393	.657	1.050	.290
R	L	ave	177	145	13	56	.304	.424	.633	1.056	.317

Rank order OPS:
min: L/R, R/R, R/L, L/L
max: R/L, L/R, R/R. L/L
average: L/R, R/L, R/R, L/L

Bat Left, Pitch Left is the worst batter performance, last in all three OPS. Batters against their opposites did the best. Percents against same:

Bat Left, Pitch Left:

		L	L	L	L	R	All	L
Player	Year	PA	AB	HR	HR/AB	HR/AB	HR/AB	HR	HRtot
Chris Davis	2013	35.51%	37.16%	24.53%	5.99%	10.90%	9.08%	13	53
Prince Fielder	2007	31.86%	32.81%	20.00%	5.32%	10.39%	8.73%	10	50
David Ortiz	2006	35.13%	36.74%	33.33%	8.78%	10.20%	9.68%	18	54
Ryan Howard	2006	31.96%	33.91%	27.59%	8.12%	10.94%	9.98%	16	58
Jim Thome	2002	31.00%	33.13%	23.08%	7.55%	12.46%	10.83%	12	52
Luis Gonzalez	2001	30.49%	30.54%	26.32%	8.06%	9.93%	9.36%	15	57
Barry Bonds	2001	28.46%	29.62%	23.29%	12.06%	16.72%	15.34%	17	73
Ken Griffey	1998	27.36%	27.96%	37.50%	11.86%	7.68%	8.85%	21	56
Ken Griffey	1997	30.82%	32.24%	25.00%	7.14%	10.19%	9.21%	14	56
Brady Anderson	1996	32.61%	32.30%	26.00%	6.95%	9.44%	8.64%	13	50
Roger Maris	1961	30.52%	30.00%	19.67%	6.78%	11.86%	10.34%	12	61
		L	L	L	L	R	All
		PA	AB	HR	HR/AB	HR/AB	HR/AB
	min	27.36%	27.96%	19.67%	5.32%	7.68%	8.64%
	max	35.51%	37.16%	37.50%	12.06%	16.72%	15.34%
	ave	31.43%	32.40%	26.03%	8.06%	10.97%	10.00%

Bat Right, Pitch Right:

R		R	R	R	R	L	All	R
Player	Year	PA	AB	HR	HR/AB	HR/AB	HR/AB	HR	HRtot
Jose Bautista	2010	81.11%	81.02%	85.19%	9.98%	7.41%	9.49%	46	54
Alex Rodriguez	2007	75.14%	76.67%	87.04%	10.51%	5.15%	9.26%	47	54
Andruw Jones	2005	78.27%	78.67%	82.35%	9.11%	7.20%	8.70%	42	51
Alex Rodriguez	2002	75.03%	74.52%	85.96%	10.54%	5.03%	9.13%	49	57
Sammy Sosa	2001	80.73%	83.88%	79.69%	10.54%	13.98%	11.09%	51	64
Alex Rodriguez	2001	79.64%	79.11%	76.92%	8.00%	9.09%	8.23%	40	52
Sammy Sosa	2000	78.16%	79.47%	84.00%	8.75%	6.45%	8.28%	42	50
Sammy Sosa	1999	73.74%	73.92%	71.43%	9.74%	11.04%	10.08%	45	63
Mark McGwire	1999	75.79%	76.58%	75.38%	12.28%	13.11%	12.48%	49	65
Greg Vaughn	1998	66.11%	66.67%	72.00%	9.42%	7.33%	8.73%	36	50
Sammy Sosa	1998	72.16%	74.49%	81.82%	11.27%	7.32%	10.26%	54	66
Mark McGwire	1998	73.13%	74.46%	78.57%	14.51%	11.54%	13.75%	55	70
Mark McGwire	1997	77.32%	78.33%	79.31%	10.87%	10.26%	10.74%	46	58
Mark McGwire	1996	76.09%	75.89%	76.92%	12.46%	11.76%	12.29%	40	52
Albert Belle	1995	74.96%	75.64%	84.00%	10.17%	6.02%	9.16%	42	50
Cecil Fielder	1990	68.05%	68.94%	50.98%	6.58%	14.04%	8.90%	26	51
George Foster	1977	61.97%	62.76%	61.54%	8.29%	8.73%	8.46%	32	52
Willie Mays	1965	71.94%	72.76%	76.92%	9.85%	7.89%	9.32%	40	52
		R	R	R	R	L	All
		PA	AB	HR	HR/AB	HR/AB	HR/AB
	min	61.97%	62.76%	50.98%	6.58%	5.03%	8.23%
	max	81.11%	83.88%	87.04%	14.51%	14.04%	13.75%
	ave	74.41%	75.21%	77.22%	10.16%	9.08%	9.91%

***   The End   ***