Find the first matched string/value from a table

2023 6 13
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更新时间：2023 6 15
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Hi,
I have got a table like below:
StepNum Activity TypeNum
5098 Stand 1-96
5099 Stand 1-96
5101 Stationary 1-96
5105 Stationary 1-96
5106 Stand 1-97
5107 Stand 1-97
5113 Stand 1-97
5114 Trenching 1-98
5115 Trenching 1-98
5116 Trenching 1-98
What I would like to do is to find the first matched of the string 'Trenching', then read the row/column number so that I can get the value/string in adjacent cells/rows. Just wondering if anyone here can help me out? Many thanks in advance.
Regards,
Kane

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Star Strider
Star Strider 2023-6-13
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Ran in:
One approach —
VN = {'StepNum' 'Activity' 'TypeNum'};
step = [5098
5099
5101
5105
5106
5107
5113
5114
5115
5116];
v23 = ["Stand" "1-96"
"Stand" "1-96"
"Stationary" "1-96"
"Stationary" "1-96"
"Stand" "1-97"
"Stand" "1-97"
"Stand" "1-97"
"Trenching" "1-98"
"Trenching" "1-98"
"Trenching" "1-98"];
T1 = table(step, v23(:,1), v23(:,2), 'VariableNames',VN)
T1 = 10×3 table
StepNum Activity TypeNum _______ ____________ _______ 5098 "Stand" "1-96" 5099 "Stand" "1-96" 5101 "Stationary" "1-96" 5105 "Stationary" "1-96" 5106 "Stand" "1-97" 5107 "Stand" "1-97" 5113 "Stand" "1-97" 5114 "Trenching" "1-98" 5115 "Trenching" "1-98" 5116 "Trenching" "1-98"
idx = find(ismember(T1{:,2}, "Trenching"));
DesiredResult = T1{idx(1),:} % Contents Of Row
DesiredResult = 1×3 string array
"5114" "Trenching" "1-98"
DesiredResult = T1(idx(1),:) % Sub-Table
DesiredResult = 1×3 table
StepNum Activity TypeNum _______ ___________ _______ 5114 "Trenching" "1-98"
.

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Kane Lok
Kane Lok 2023-6-14
编辑：Kane Lok 2023-6-14
Hi Star Strider,
Thanks for the help first.
The command of 'DesiredResult = T1{idx(1),:}' is not working, and I think it is down to the fact that I didn't explain my application thoroughly.
Basically I import a table from an excel file by using the following command:
data = readtable('InputFile.xlsx','Sheet','RecordInfo','range','A:K');
Once I have got 'data' in my MATLAB workspace, I then search for the first matched 'Trenching' and get the row number. So I could read the relevant TypeNum cell content and read other cell contents (like Volt and Current) in the previous rows (like stand and stationary) (i.e. the table that I posted intially is only a small part of the data).
StepNum Activity TypeNum Volt Current
_______ ____________ _______ ____ _______
5098 "Stand" "1-96" 1.1 0.1
5099 "Stand" "1-96" 1.2 0.2
5101 "Stationary" "1-96" 1.3 0.3
5105 "Stationary" "1-96" 1.3 0.3
5106 "Stand" "1-97" 1.8 0.8
5107 "Stand" "1-97" 2 0
5113 "Stand" "1-97" 1.9 1.9
5114 "Trenching" "1-98" 8 79
5115 "Trenching" "1-98" 11.5 80.5
5116 "Trenching" "1-98" 24 80.2
Those retrived cell content values will be used in a calculation to produce the results like R = (Volt(5114) - Volt(5113)) / (Current(5114) - Current(5113)). The calculated R will be used to produce another table.
Hopefully it is making sense to you and you are able to give me some suggestion? Thanks a lot.
Regards,
Kane
Star Strider
Star Strider 2023-6-14
Attach the Excel file. Use the ‘paperclip’ icon in the top toolbar to do that.
My code returns the necessary information, however I had to create it from the text since the Excel file was not provided. In any event, to use the information my code in my answer returns, use the str2double function to retrieve the numeric results. This might not be necessary using the actual Excel file.
Kane Lok
Kane Lok 2023-6-15
移动：Star Strider 2023-6-15
Hi Star Strider,
The excel file attached and thanks for your help.
Regards,
Kane
Star Strider
Star Strider 2023-6-15
Ran in:
Ran in:
My pleasure!
Try this (including a calculation for ‘R’) —
T1 = readtable('activity_table.xlsx', 'VariableNamingRule','preserve')
T1 = 2307×9 table
SignNum StepName ActivityStepNum LoopNum StepNum Current(A) Voltage(V) Power(W) RelativeTime(d.h:min:s.ms) _______ _________ _______________ _______ _______ __________ __________ ________ __________________________ 1 {'Stand'} {'1-1'} 1 1 0 3.5252 0 {'0.00:01:00.000'} 2 {'Stand'} {'1-1'} 1 1 0 3.5252 0 {'0.00:02:00.000'} 3 {'Stand'} {'1-1'} 1 1 0 3.5252 0 {'0.00:03:00.000'} 4 {'Stand'} {'1-1'} 1 1 0 3.5253 0 {'0.00:04:00.000'} 5 {'Stand'} {'1-1'} 1 1 0 3.5253 0 {'0.00:05:00.000'} 6 {'Stand'} {'1-1'} 1 1 0 3.5252 0 {'0.00:06:00.000'} 7 {'Stand'} {'1-1'} 1 1 0 3.5253 0 {'0.00:07:00.000'} 8 {'Stand'} {'1-1'} 1 1 0 3.5253 0 {'0.00:08:00.000'} 9 {'Stand'} {'1-1'} 1 1 0 3.5252 0 {'0.00:09:00.000'} 10 {'Stand'} {'1-1'} 1 1 0 3.5252 0 {'0.00:10:00.000'} 11 {'Stand'} {'1-1'} 1 1 0 3.5253 0 {'0.00:11:00.000'} 12 {'Stand'} {'1-1'} 1 1 0 3.5253 0 {'0.00:12:00.000'} 13 {'Stand'} {'1-1'} 1 1 0 3.5253 0 {'0.00:13:00.000'} 14 {'Stand'} {'1-1'} 1 1 0 3.5253 0 {'0.00:14:00.000'} 15 {'Stand'} {'1-1'} 1 1 0 3.5253 0 {'0.00:15:00.000'} 16 {'Stand'} {'1-1'} 1 1 0 3.5252 0 {'0.00:16:00.000'}
VN = T1.Properties.VariableNames;
idx = find(ismember(T1{:,2}, "Trenching"))
idx = 1347×1
930 931 932 933 934 935 936 937 938 939
DesiredResult = T1(idx(1)+[-1 1],:) % Contents Of Row
DesiredResult = 2×9 table
SignNum StepName ActivityStepNum LoopNum StepNum Current(A) Voltage(V) Power(W) RelativeTime(d.h:min:s.ms) _______ _____________ _______________ _______ _______ __________ __________ ________ __________________________ 929 {'Stand' } {'1-3'} 1 3 0 4.19 0 {'0.01:00:00.000'} 931 {'Trenching'} {'1-4'} 1 4 -17.001 4.1828 -71.11 {'0.00:00:00.020'}
Volt = DesiredResult{:,ismember(VN,'Voltage(V)')}
Volt = 2×1
4.1900 4.1828
Current = DesiredResult{:,ismember(VN,'Current(A)')}
Current = 2×1
0 -17.0006
R = (Volt(2) - Volt(1)) / (Current(2) - Current(1))
R = 4.2351e-04
See if that does what you want.
.

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