Remove empty rows from matrix
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Hi folks,
I have the following matrix:
0.6857 0.1248 0.9636 1.0884 0.4807 0.6077 0.3644 0 0 0
0.9093 1.0006 1.0006 1.0006 1.0006 0.3702 0 0 0 0
0.6367 1.0106 0.5669 0.4437 1.0106 1.0106 0.4608 0 0 0
0.2100 0.3250 1.1000 0.9750 0.1250 1.1000 0.4070 0 0 0
0.2048 0.4401 0.7116 1.1518 0.1521 0.2741 0 0 0 0
0.5575 0.2119 1.2212 0.3091 0.9121 0.8300 0.0993 0 0 0
0.6041 1.0239 0.6050 0.4189 1.0239 0.3428 0 0 0 0
0.5817 1.0205 0.4559 0.5645 1.0205 0.3417 0 0 0 0
0.9277 1.0209 0.5690 0.4519 1.0209 1.0209 0.4390 0 0 0
0.1817 1.0217 0.7974 0.2243 0.4393 0 0 0 0 0
0.4787 0.9174 0.2224 1.1398 0.7216 0.4182 0.3816 0 0 0
0.9091 1.0004 1.0004 1.0004 1.0004 0.5803 0 0 0 0
0.2126 1.0104 0.1849 1.1953 0.4451 0.2482 0 0 0 0
0.2531 0.2652 1.0657 1.0657 0.4962 0.5695 0.7034 0 0 0
0.2072 0.8844 0.2805 1.1650 0.5038 0.2651 0 0 0 0
0.3229 1.0774 0.0362 1.1136 1.1136 0.0092 0.3636 0 0 0
0.2172 1.2212 0.0671 1.1541 0.5882 0.2788 0 0 0 0
0.3084 1.0633 1.0633 0.3386 0.4706 0 0 0 0 0
0.2108 1.0037 1.0037 1.0037 0.3361 0 0 0 0 0
0.1521 0.0784 1.0078 1.0862 0.4669 0.6193 0.3637 0 0 0
0.9111 1.0026 1.0026 1.0026 1.0026 0.8622 0 0 0 0
0.1406 1.0046 1.0046 1.0046 1.0046 1.0046 1.0046 0.5075 0 0
0.1918 0.0487 1.0297 1.0784 0.5640 0.3634 0 0 0 0
0.1513 0.0229 1.2441 0.4140 0.8301 0.8509 0.0958 0 0 0
0.8749 1.0001 1.0001 0.0422 0 0 0 0 0 0
0.8900 1.0173 0.5089 0.5084 1.0173 1.0173 0.5565 0 0 0
0.8903 1.0177 0.7745 0 0 0 0 0 0 0
1.0498 0.0125 1.2351 0.4561 0.7790 0.4136 0 0 0 0
1.0150 0.7605 0.4198 0.8982 0 0 0 0 0 0
0.1808 1.0165 1.0165 1.0165 0.1931 0 0 0 0 0
0.8158 1.0071 0.2857 0.4807 0 0 0 0 0 0
0.8973 0.2251 0.9714 0.8502 0.3462 0.4006 0 0 0 0
0.2134 1.2000 0.1495 1.0506 0.7584 0.4417 0.3000 0 0 0
0.7503 1.0005 1.0005 1.0005 1.0005 0.5472 0 0 0 0
0.8519 1.1359 0.0001 0.8643 0 0 0 0 0 0
0.7315 0.4265 0.7546 0.3955 0 0 0 0 0 0
0.6675 0.8202 0 0 0 0 0 0 0 0
0.3814 1.0037 1.0037 1.0037 0.5490 0 0 0 0 0
0.3608 1.0934 0.0694 0.2967 0 0 0 0 0 0
0.1815 1.0204 1.0204 1.0204 1.0204 0.0804 0.6033 0 0 0
0.3523 1.0676 1.0676 0.0248 1.0429 0.5840 0 0 0 0
0.3721 0.6114 0.6717 0.4296 0 0 0 0 0 0
0.1866 1.0493 1.0493 0.5664 0.4830 1.0493 0.7450 0 0 0
0.2975 1.0260 0.0635 0.9624 1.0260 0.5612 0 0 0 0
0.3385 0.8884 0 0 0 0 0 0 0 0
0.2690 0.8727 0.3151 0.3977 0 0 0 0 0 0
0.2374 1.0482 0.7679 0.2802 1.0482 0.5733 0 0 0 0
0.1428 1.0986 0.2470 0.1208 0 0 0 0 0 0
0.1407 1.0821 1.0821 0.1822 0.8999 0.5919 0 0 0 0
0.1300 0.7610 0 0 0 0 0 0 0 0
0.9675 0.0053 0.4343 0 0 0 0 0 0 0
0.1817 1.0220 1.0220 1.0220 0.9418 0.0802 1.0220 0.2555 0 0
0.8054 1.0738 0.0971 0.9767 0.5874 0 0 0 0 0
0.7961 0.2463 0.5288 0 0 0 0 0 0 0
0.6895 0.6923 0.3524 1.0447 0.5715 0 0 0 0 0
0.6871 0 0 0 0 0 0 0 0 0
0.9155 0 0 0 0 0 0 0 0 0
0.4147 0 0 0 0 0 0 0 0 0
0.7308 0.0113 1.1596 0.8044 0.3522 0 0 0 0 0
0.6601 0.3453 0 0 0 0 0 0 0 0
0.5076 0.0782 0 0 0 0 0 0 0 0
0.7649 0.2744 0.5651 0 0 0 0 0 0 0
0.6115 0.3237 0.1214 0 0 0 0 0 0 0
0.7236 0.0776 0.6387 0 0 0 0 0 0 0
0.5311 0.1151 0.9963 0 0 0 0 0 0 0
0.1641 0.0599 0.9660 1.0259 0.5612 0 0 0 0 0
0.8965 0 0 0 0 0 0 0 0 0
0.6188 1.0043 0.1607 0 0 0 0 0 0 0
0.4533 0.3284 0.9263 0 0 0 0 0 0 0
0.3628 0.4568 0.4365 0 0 0 0 0 0 0
0.2558 0.5884 0 0 0 0 0 0 0 0
0.1884 0.4902 0 0 0 0 0 0 0 0
0.1455 0.0447 0.5526 0 0 0 0 0 0 0
0.0793 0.3838 0 0 0 0 0 0 0 0
0.0805 1.0149 0.6064 0 0 0 0 0 0 0
0.7523 0.8290 0.2982 1.1272 0.5694 0 0 0 0 0
0.1034 0.9373 0.3661 1.1931 0.1102 0.7427 0 0 0 0
0.0888 0.4431 0.6763 0.0638 0 0 0 0 0 0
0.0670 0.3839 0 0 0 0 0 0 0 0
0.0681 1.0164 0.6073 0 0 0 0 0 0 0
0.0755 0.4427 0.6843 0.0642 0 0 0 0 0 0
0.5619 0.4598 0.6869 1.1467 0.2045 0 0 0 0 0
0.4987 0.3906 0 0 0 0 0 0 0 0
0.5430 0.0114 1.0968 0.0632 0 0 0 0 0 0
0.4407 0.4027 0 0 0 0 0 0 0 0
0.4495 1.0963 0.2350 0.8613 0.5538 0 0 0 0 0
0.5038 0.4028 0 0 0 0 0 0 0 0
0.4943 0.0541 1.1424 0.0651 0 0 0 0 0 0
0.6954 0.4171 0 0 0 0 0 0 0 0
0.4677 0.2769 1.1634 0.0663 0 0 0 0 0 0
0.1589 1.1350 0.2493 0.8856 0.5733 0 0 0 0 0
0.3814 0.0163 1.2831 0.0731 0 0 0 0 0 0
0.6389 1.0369 0.4251 0 0 0 0 0 0 0
0.0710 1.0149 0.5551 0 0 0 0 0 0 0
0.4376 0.6881 1.0147 0 0 0 0 0 0 0
0.6393 1.1416 0.2036 0 0 0 0 0 0 0
0.3888 1.0800 0.1926 0 0 0 0 0 0 0
0.6852 0.3812 0 0 0 0 0 0 0 0
0.4217 0.7882 0.3831 0.6674 0 0 0 0 0 0
0.2469 1.0330 0.1550 0.2272 0 0 0 0 0 0
0.6003 0.1677 0.6004 0 0 0 0 0 0 0
0.3019 0.1893 1.0737 0.5634 0.0933 0 0 0 0 0
0.8692 0.1094 0.5962 0 0 0 0 0 0 0
0.3294 0.5862 0.7919 0.6614 0.0828 0 0 0 0 0
0.3616 1.1205 0.0095 0.5708 0 0 0 0 0 0
0.9761 0.2160 0.9891 0.4625 0 0 0 0 0 0
0.1902 1.0011 0.5057 0 0 0 0 0 0 0
0.2418 1.0338 1.0338 0.5295 0 0 0 0 0 0
0.2351 1.0051 0.1556 0.8495 0.4699 0 0 0 0 0
0.2517 1.0759 1.0233 0.0526 0.5968 0 0 0 0 0
0.2342 1.0014 1.0014 0.4238 0 0 0 0 0 0
0.2430 1.0389 0.9815 0.0574 0.4320 0 0 0 0 0
0.2707 0.5728 0.5845 1.1573 0.2449 0.2636 0 0 0 0
0.1065 0.1941 1.2852 0.1126 1.1726 0.4194 0.2113 0 0 0
0.5830 0.5932 0 0 0 0 0 0 0 0
0.4807 0.7002 0.5100 1.2102 0.0551 0.4094 0 0 0 0
0.8563 0.0122 0.5702 0 0 0 0 0 0 0
0.1487 0.9660 0.3856 0.3652 0 0 0 0 0 0
0.7246 0.1034 0.4980 0 0 0 0 0 0 0
0.2777 0.7889 0.3046 0 0 0 0 0 0 0
Columns 11 through 20
0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0
I want to remove all the rows which are all zeros.
Thanks
采纳的回答
Star Strider
2018-9-17
If ‘M’ is your matrix, this works:
M = M(~all(M == 0, 2),:);
It will remove the ‘all zero’ rows using ‘logical indexing’.
4 个评论
Harry Saner
2020-3-28
This was really helpful thanks!
what does the 2 do or mean? I can see that it's basically saying for M the rows of the matrix M "not all" the elements that are equal to 0 must be removed
but how would you explain each part of that line of code in words?
Star Strider
2020-3-29
My pleasure!
The code assigns to ‘M’ the rows of the original ‘M’ that do not have all the elements of each row equal to 0.
It has the effect of elimiinating the rows in which all the elements of the row are equal to 0. The ‘2’ dimension argument to the all function tells the all function to look along the rows (rather than the columns, that would be the default dimension 1). The first part of the code:
~all(M == 0, 2)
creates the logical row index, and the code assigna all the columns in the original matrix (using the wildcard ‘:’) where the row argument logical index is true, or logical 1.
Thiago de Aquino Costa Sousa
2022-11-23
And what if, instead of 0 I have empty [] cells??? How can I remove them?
@Thiago de Aquino Costa Sousa: If you have a cell array (not a matrix as in the question) and you want to remove those rows whose elements all contain the empty array [], then you can do this:
% a cell array with some cells containing empty arrays []:
C = {1 [] 3; [] [] []; [7 8] [] []}
C = C(~all(cellfun(@isempty,C),2),:)
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