Sorting data from specific row

Hi expert,

Suppose that I have the following [n x 4] matrix where the last column is the row index.

I want to sort this matrix based on its index starts from row 58, i.e. row 58 becomes row 1.

I have copied the expected result below. As you can see, idx 58 has now become idx 1. I have created this output manually and wondering if we can create a program for this operation.

I hope it is easier for you to understand what I am trying to achieve.

data=[
%   C        x          y          idx
%=======================================
    5.6073   -0.0976   -0.9941    1.0000
   13.4173   -0.2308   -0.9675    2.0000
   22.4240   -0.3846   -0.9320    3.0000
   32.8868   -0.5414   -0.8373    4.0000
   39.9133   -0.6509   -0.7781    5.0000
   48.8753   -0.7692   -0.6716    6.0000
   55.0737   -0.8432   -0.5888    7.0000
   60.7391   -0.9083   -0.5089    8.0000
   65.5056   -0.9675   -0.4408    9.0000
   70.2820   -1.0237   -0.3669   10.0000
   75.0905   -1.0888   -0.2899   11.0000
   77.7703   -1.1331   -0.2456   12.0000
   81.1032   -1.1716   -0.1834   13.0000
   84.2605   -1.2367   -0.1243   14.0000
   86.7016   -1.2840   -0.0740   15.0000
   90.7816   -1.3047    0.0178   16.0000
   93.7990   -1.3373    0.0888   17.0000
   97.7415   -1.3491    0.1834   18.0000
  101.9127   -1.3462    0.2840   19.0000
  105.4733   -1.3254    0.3669   20.0000
  109.3020   -1.2840    0.4497   21.0000
  111.2655   -1.2544    0.4882   22.0000
  113.0971   -1.2071    0.5148   23.0000
  115.9221   -1.1686    0.5680   24.0000
  119.2205   -1.1213    0.6272   25.0000
  122.2223   -1.0562    0.6657   26.0000
  124.7305   -1.0030    0.6953   27.0000
  128.5472   -0.9320    0.7426   28.0000
  133.2641   -0.8550    0.8047   29.0000
  138.3187   -0.7692    0.8639   30.0000
  142.1259   -0.7041    0.9053   31.0000
  146.3541   -0.6183    0.9290   32.0000
  150.1586   -0.5533    0.9645   33.0000
  154.2771   -0.4675    0.9704   34.0000
  159.8625   -0.3580    0.9763   35.0000
  167.3069   -0.2219    0.9852   36.0000
  174.1348   -0.1006    0.9793   37.0000
  179.8245   -0.0030    0.9793   38.0000
  182.0951    0.0355    0.9704   39.0000
  188.6575    0.1464    0.9615   40.0000
  194.0578    0.2352    0.9393   41.0000
  198.1323    0.3018    0.9216   42.0000
  204.6068    0.4038    0.8817   43.0000
  209.8847    0.4837    0.8417   44.0000
  217.9093    0.6036    0.7751   45.0000
  223.9603    0.6790    0.7041   46.0000
  228.7075    0.7411    0.6509   47.0000
  233.1990    0.7988    0.5976   48.0000
  237.3932    0.8787    0.5621   49.0000
  240.8265    0.9275    0.5178   50.0000
  245.2960    0.9808    0.4512   51.0000
  248.9525    1.0340    0.3979   52.0000
  252.7702    1.0828    0.3358   53.0000
  256.3519    1.1272    0.2737   54.0000
  260.5377    1.1538    0.1923   55.0000
  264.5124    1.2012    0.1154   56.0000
  267.3981    1.2367    0.0562   57.0000
  269.8639    1.2633    0.0030   58.0000
  272.1048    1.2870   -0.0473   59.0000
  275.2524    1.3195   -0.1213   60.0000
  276.7260    1.3550   -0.1598   61.0000
  279.5405    1.3905   -0.2337   62.0000
  282.2006    1.4231   -0.3077   63.0000
  285.6266    1.4172   -0.3964   64.0000
  287.9931    1.3846   -0.4497   65.0000
  289.9505    1.3284   -0.4822   66.0000
  293.5338    1.2840   -0.5592   67.0000
  296.9429    1.2515   -0.6361   68.0000
  300.1697    1.2367   -0.7189   69.0000
  303.1574    1.1864   -0.7751   70.0000
  305.9150    1.1479   -0.8314   71.0000
  308.6397    1.0769   -0.8609   72.0000
  311.1835    1.0178   -0.8905   73.0000
  314.8198    0.9408   -0.9349   74.0000
  316.9771    0.8698   -0.9320   75.0000
  319.5037    0.7959   -0.9320   76.0000
  321.3839    0.7160   -0.8964   77.0000
  323.9515    0.6568   -0.9024   78.0000
  327.0877    0.5917   -0.9142   79.0000
  330.8083    0.5207   -0.9320   80.0000
  338.2939    0.3757   -0.9438   81.0000
  345.6466    0.2574   -1.0059   82.0000
  355.9860    0.0710   -1.0118   83.0000];

The expected output is below

aftersorting=[
%   C             x    y      idx   newidx
%=======================================
269.8639	1.2633	0.003	58	1
267.3981	1.2367	0.0562	57	2
264.5124	1.2012	0.1154	56	3
260.5377	1.1538	0.1923	55	4
256.3519	1.1272	0.2737	54	5
252.7702	1.0828	0.3358	53	6
248.9525	1.034	0.3979	52	7
245.296	0.9808	0.4512	51	8
240.8265	0.9275	0.5178	50	9
237.3932	0.8787	0.5621	49	10
233.199	0.7988	0.5976	48	11
228.7075	0.7411	0.6509	47	12
223.9603	0.679	0.7041	46	13
217.9093	0.6036	0.7751	45	14
209.8847	0.4837	0.8417	44	15
204.6068	0.4038	0.8817	43	16
198.1323	0.3018	0.9216	42	17
194.0578	0.2352	0.9393	41	18
188.6575	0.1464	0.9615	40	19
182.0951	0.0355	0.9704	39	20
179.8245	-0.003	0.9793	38	21
174.1348	-0.1006	0.9793	37	22
167.3069	-0.2219	0.9852	36	23
159.8625	-0.358	0.9763	35	24
154.2771	-0.4675	0.9704	34	25
150.1586	-0.5533	0.9645	33	26
146.3541	-0.6183	0.929	32	27
142.1259	-0.7041	0.9053	31	28
138.3187	-0.7692	0.8639	30	29
133.2641	-0.855	0.8047	29	30
128.5472	-0.932	0.7426	28	31
124.7305	-1.003	0.6953	27	32
122.2223	-1.0562	0.6657	26	33
119.2205	-1.1213	0.6272	25	34
115.9221	-1.1686	0.568	24	35
113.0971	-1.2071	0.5148	23	36
111.2655	-1.2544	0.4882	22	37
109.302	-1.284	0.4497	21	38
105.4733	-1.3254	0.3669	20	39
101.9127	-1.3462	0.284	19	40
97.7415	-1.3491	0.1834	18	41
93.799	-1.3373	0.0888	17	42
90.7816	-1.3047	0.0178	16	43
86.7016	-1.284	-0.074	15	44
84.2605	-1.2367	-0.1243	14	45
81.1032	-1.1716	-0.1834	13	46
77.7703	-1.1331	-0.2456	12	47
75.0905	-1.0888	-0.2899	11	48
70.282	-1.0237	-0.3669	10	49
65.5056	-0.9675	-0.4408	9	50
60.7391	-0.9083	-0.5089	8	51
55.0737	-0.8432	-0.5888	7	52
48.8753	-0.7692	-0.6716	6	53
39.9133	-0.6509	-0.7781	5	54
32.8868	-0.5414	-0.8373	4	55
22.424	-0.3846	-0.932	3	56
13.4173	-0.2308	-0.9675	2	57
5.6073	-0.0976	-0.9941	1	58
355.986	0.071	-1.0118	83	59
345.6466	0.2574	-1.0059	82	60
338.2939	0.3757	-0.9438	81	61
330.8083	0.5207	-0.932	80	62
327.0877	0.5917	-0.9142	79	63
323.9515	0.6568	-0.9024	78	64
321.3839	0.716	-0.8964	77	65
319.5037	0.7959	-0.932	76	66
316.9771	0.8698	-0.932	75	67
314.8198	0.9408	-0.9349	74	68
311.1835	1.0178	-0.8905	73	69
308.6397	1.0769	-0.8609	72	70
305.915	1.1479	-0.8314	71	71
303.1574	1.1864	-0.7751	70	72
300.1697	1.2367	-0.7189	69	73
296.9429	1.2515	-0.6361	68	74
293.5338	1.284	-0.5592	67	75
289.9505	1.3284	-0.4822	66	76
287.9931	1.3846	-0.4497	65	77
285.6266	1.4172	-0.3964	64	78
282.2006	1.4231	-0.3077	63	79
279.5405	1.3905	-0.2337	62	80
276.726	1.355	-0.1598	61	81
275.2524	1.3195	-0.1213	60	82
272.1048	1.287	-0.0473	59	83
];

Answer 1

[Image Analyst]

Try this:

aftersorting = circshift(flipud(data), 58)

[BeeTiaw]

Wow...problem solved!

[BeeTiaw]

can you explain what is this line actuall does?

[Image Analyst]

flipud() flips the matrix up/down so that the last row is at the top, and the first row is at the bottom. So now row 81 is at the top and row 1 is at the bottom.

circshift() just circulalry shifts the array upwards by some amount. Rows that shift up past the first row, reappear on the bottom row. Kind of like you just rotated your belt around your waist.