MATLAB: How Can I Get MATLAB To Parse Data From 2 Arrays

floating pointMATLABmulti arrayparse

I’ve got 2 arrays that contain timed tagged data. For example, Array A contains 336 lines of data such as this:
NaN 58000.5940000000 -1177.51280000000 5508.35030000000 3007.06600000000
NaN 58002.5620000000 -1178.53030000000 5509.18320000000 3007.87480000000
NaN 58004.4920000000 -1179.45020000000 5511.39770000000 3006.62500000000
NaN 58006.7030000000 -1179.94570000000 5511.93340000000 3006.97660000000
NaN 58008.8950000000 -1181.93950000000 5513.33510000000 3007.40650000000
NaN 58010.7110000000 -1185.03380000000 5515.23320000000 3008.92190000000
NaN 58012.2970000000 -1188.73180000000 5516.97960000000 3010.23010000000
NaN 58014.7150000000 -1191.21170000000 5518.12650000000 3009.92960000000
NaN 58016.8710000000 -1194.66150000000 5519.85710000000 3010.63770000000
NaN 58018.5740000000 -1199.73790000000 5521.98280000000 3012.15330000000
Array B contains 251 lines of data such as the following:
57942.7148437500 2 -5165.91064453000 696.920776367000 5687.62695312500 2.44455700000000e-13
58002.5619062500 2 -5174.50097656000 686.538391113000 5681.06005859400 1.05495600000000e-21
58005.9960937500 2 -5182.81396484000 676.470520019000 5674.66943359400 1.16348400000000e-10
58006.7031875000 2 -5191.15625000000 666.347106933000 5668.22216796900 1.30795700000000e-18
58010.5546875000 3 -5224.20361328000 626.038818359000 5642.33007812500 1.17064600000000e-22
58012.2969750000 3 -5232.68701171000 615.638122558000 5635.59277343800 1.16924600000000e-16
58013.2969750000 3 -5232.68701171000 615.638122558000 5635.59277343800 1.16924600000000e-12
58016.8713562500 3 -5240.89648437000 605.552246093000 5629.03662109400 1.30593000000000e-13
The intent is to parse out, and use, the rows of data in array A (minus the NaNs), and all rows of data in array B – but only when the time tags in array A (column 2) are the same as the time tags in array B (column 1), to 2 decimal places.
For the above arrays, the data associated with time tags 58002.56, 58006.70, 58012.29, and 58016.87 are the targets.
I’ve been reviewing the MATLAB documentation center for reference to a command that would read/match these values, but can’t find one. In the event no such command exists, what would be a sensible approach to parsing out the data of 2 arrays?

Best Answer

First round the time columns to 2 digits -- probably easiest way to do this is to just make use of the i/o runtime...
A(:,2)==str2num(num2str(A(:,2),'%.2f')); % round to two decimal places B(:,1)==str2num(num2str(B(:,1),'%.2f')); % ditto
Then just use union to find the indices in A and B that are in common for the two columns
[~,ia,ib]=union(A(:,2),B(:,1)); U=[A(ia,:) B(ib,:)];
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