country	id	ind	nta	mbv	ta	td	se	ns	ebit	oi
Austrilia	1	1	8709.43	8.65	10028.3	331.7828	2588.14	0	-6377.19	-4238.99
Austrilia	3	1	27837.84	0.3	30800.53	558.1616	1546.03	0	-1777.06	-1550.65
Austrilia	5	1	92530.06	3.46	93334.67	0	1768.41	0	-442.2	-2007.76
Austrilia	6	1	1034.34	6.15	1228.83	0	2805.87	160.9566	-2631.15	-2672.03
Austrilia	7	0	4616.5	1.7	4878.31	50.90823	5083.5	0	-5401.59	-5336.35
Austrilia	8	1	2626.02	1.13	2824.02	0	952.8115	0	-10421	-972.91
Austrilia	9	2	3005850	1.38	3609290	595217.9	12105.82	0	6745.99	-12105.8
China	342	0	232753.4	2.23	566987.5	183097.7	34828.78	426337.5	15526.25	-2441.68
China	343	0	150293.6	6.86	539169.5	90882.83	82443.54	838204.2	59926.4	53283.41
China	344	0	306463.5	4.9	495364.4	43222.05	76709.31	323914	46041.55	35952.56
China	345	1	116672.6	4.89	491790.9	103453.9	59065.04	536070.7	30213.98	29899.71
China	346	1	183873.4	3.54	426193.9	88149.7	21730.88	370313	11490.04	4141.99
China	347	1	84033.18	2.85	419652.6	139535.1	33500.32	178246.1	10317.18	3666.7
China	348	1	112584.4	3.36	418753.3	214085.5	61569.6	336384.8	17489.7	13509.9
US	675	0	543.9531	17.66	2164.3	23.348	5037.77	14705.43	335.8669	328.624
US	676	0	400939	0.99	571440.6	4897	434155.5	1788140	38682.99	38694
US	677	0	-188310	-0.01	101514	49404	162441	502316.8	-222450	-71354

再次讨教 不胜感激！！！目标是对每个国家每个ind的每个变量求平均值
for example:
对Austrilia的ind=1的所有nta求mean，再对对Austrilia的ind=0的所有nta求mean.。。以此类推
得到的平均值变量起名为nta， mbvm等等以此类推，放再原表格之后的列

country	id	ind	nta	mbv	ta	td	se	ns	ebit	oi	ntam	mbvm	tam
Austrilia	1	1	8709.43	8.65	10028.3	331.7828	2588.14	0	-6377.19	-4238.99
Austrilia	3	1	27837.84	0.3	30800.53	558.1616	1546.03	0	-1777.06	-1550.65
Austrilia	5	1	92530.06	3.46	93334.67	0	1768.41	0	-442.2	-2007.76
Austrilia	6	1	1034.34	6.15	1228.83	0	2805.87	160.9566	-2631.15	-2672.03
Austrilia	7	0	4616.5	1.7	4878.31	50.90823	5083.5	0	-5401.59	-5336.35
Austrilia	8	0	2626.02	1.13	2824.02	0	952.8115	0	-10421	-972.91
Austrilia	9	0	3005850	1.38	3609290	595217.9	12105.82	0	6745.99	-12105.8
China	342	0	232753.4	2.23	566987.5	183097.7	34828.78	426337.5	15526.25	-2441.68
China	343	0	150293.6	6.86	539169.5	90882.83	82443.54	838204.2	59926.4	53283.41
China	344	0	306463.5	4.9	495364.4	43222.05	76709.31	323914	46041.55	35952.56
China	345	1	116672.6	4.89	491790.9	103453.9	59065.04	536070.7	30213.98	29899.71
China	346	2	183873.4	3.54	426193.9	88149.7	21730.88	370313	11490.04	4141.99
China	347	3	84033.18	2.85	419652.6	139535.1	33500.32	178246.1	10317.18	3666.7
China	348	4	112584.4	3.36	418753.3	214085.5	61569.6	336384.8	17489.7	13509.9
US	675	0	543.9531	17.66	2164.3	23.348	5037.77	14705.43	335.8669	328.624
US	676	0	400939	0.99	571440.6	4897	434155.5	1788140	38682.99	38694
US	677	0	-188310	-0.01	101514	49404	162441	502316.8	-222450	-71354

我试图用循环去做，无奈水平太差，只得再爬上来求教