Getting structure content using strings

2018 8 10
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更新时间：2018 8 11
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I have kt containing data type "strings", one of them is "grad"i.e kt(1,1)=grad which is a string. I am also trying to get the content of the structure(Data.edata.grad) in my data using the string data set by doing Data.edata.kt(1,1) but i am getting the error kt(1,1) is not an existing field. How can i convert a string to a structure or how can i use my string data set to get the structures?

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James Tursa
James Tursa 2018-8-10
Show us the actual code, not your description of it. And copy & paste the entire error message for us to see.
samuel okeleye
samuel okeleye 2018-8-11
编辑：Walter Roberson 2018-8-11
clear;
clc;
load('Unit 1001 Session 0068.mat')
k=Data.ECU_Data;
m=Data.Continuous_Data;
%CREATING THE FIELDS THAT NEED TO BE CHECKED
fieldcheck={'spn00084_src00_wheel_based_vehicle_speed';...
'spn00190_src00_engine_speed';...
'spn00102_src00_engine_intake_manifold_1_pressure';...
'spn00105_src00_engine_intake_manifold_1_temperature';...
'spn00108_src00_barometric_pressure';...
'spn00513_src00_actual_engine___percent_torque';...
'spn00110_src00_engine_coolant_temperature';...
'spn00183_src00_engine_fuel_rate';...
'spn00514_src00_nominal_friction___percent_torque';...
'spn00528_src00_engine_speed_at_point_2_engine_configuration';...
'spn00529_src00_engine_speed_at_point_3_engine_configuration';...
'spn00530_src00_engine_speed_at_point_4_engine_configuration';...
'spn00531_src00_engine_speed_at_point_5_engine_configuration';...
'spn00540_src00_engine_percent_torque_at_point_2_engine_configur';...
'spn00541_src00_engine_percent_torque_at_point_3_engine_configur';...
'spn00542_src00_engine_percent_torque_at_point_4_engine_configur';...
'spn00543_src00_engine_percent_torque_at_point_5_engine_configur';...
'spn00544_src00_engine_reference_torque_engine_configuration';...
'spn04154_src00_actual_engine___percent_torque_high_resolution';...
'spn03700_src00_diesel_particulate_filter_active_regeneration_st'};
fieldcheck2={'ambient.temperature';...
'vehicle.speed.gps';...
'vehicle.position.latitude';...
'vehicle.position.longitude';...
'vehicle.position.altitude'};
%%Channel Existence Check
af1=isfield(k,{'spn00084_src00_wheel_based_vehicle_speed';...
'spn00190_src00_engine_speed';...
'spn00102_src00_engine_intake_manifold_1_pressure';...
'spn00105_src00_engine_intake_manifold_1_temperature';...
'spn00108_src00_barometric_pressure';...
'spn00513_src00_actual_engine___percent_torque';...
'spn00110_src00_engine_coolant_temperature';...
'spn00183_src00_engine_fuel_rate';...
'spn00514_src00_nominal_friction___percent_torque';...
'spn00528_src00_engine_speed_at_point_2_engine_configuration';...
'spn00529_src00_engine_speed_at_point_3_engine_configuration';...
'spn00530_src00_engine_speed_at_point_4_engine_configuration';...
'spn00531_src00_engine_speed_at_point_5_engine_configuration';...
'spn00540_src00_engine_percent_torque_at_point_2_engine_configur';...
'spn00541_src00_engine_percent_torque_at_point_3_engine_configur';...
'spn00542_src00_engine_percent_torque_at_point_4_engine_configur';...
'spn00543_src00_engine_percent_torque_at_point_5_engine_configur';...
'spn00544_src00_engine_reference_torque_engine_configuration';...
'spn04154_src00_actual_engine___percent_torque_high_resolution';...
'spn03700_src00_diesel_particulate_filter_active_regeneration_st'});
af2=isfield(m,{'ambient.temperature';...
'vehicle.speed.gps';...
'vehicle.position.latitude';...
'vehicle.position.longitude';...
'vehicle.position.altitude'});
%Available and Unavailable Channels
af1av=fieldcheck(af1==1);
af1unav=fieldcheck(af1==0);
%
af2av=fieldcheck2(af2==1);
af2unav=fieldcheck2(af2==0);
avk=k.af1av
Error
Reference to non-existent field 'af1av'.
Error in QA_QC (line 86)
avk=k.af1av;
samuel okeleye
samuel okeleye 2018-8-11
I switched the string to cell for simplicity.

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 采纳的回答

Walter Roberson
Walter Roberson 2018-8-11

0 个投票

Data.edata.(kt(1,1))
You might perhaps need to use
Data.edata.(kt{1,1})

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samuel okeleye
samuel okeleye 2018-8-11
This worked for a single entry. However i have 19 rows and 1 column and it did not work for the rest. I have also changed the data type from string to a different data type for simplicity. Thanks for your assistance
Walter Roberson
Walter Roberson 2018-8-11
Note that isfield() returns logical directly, so
af1av=fieldcheck(af1==1);
af1unav=fieldcheck(af1==0);
can be written as just
af1av = fieldcheck(af1);
af1unav = fieldcheck(~af1);
Also, you do not need to code those text strings twice: you can
af1 = isfield(k, fieldcheck);
Anyhow, we have as outsider viewers have no reason to expect that af1av will be a scalar cell array containing only one character vector, so k referenced with fields af1av would be expected to referencing multiple fields. You cannot use the .(field) dynamic fieldname syntax to access multiple fields.
You should consider a different approach such as
kcell = struct2cell(k);
af1 = cell2struct( kcell(af1), af1av, 1); %not sure that 1 is correct here, possibly 2 instead.
samuel okeleye
samuel okeleye 2018-8-11
编辑：Walter Roberson 2018-8-11
Thanks for your help. Because k contains a lot of structures, out of which i am selecting few,kcell(af1) only selected the first set of structures within k, through the length of af1. I tried the method below and it worked. Please advise if you think my method is complicated. Thanks
for i=1:length(af1av)
af1avchannel(i)=k.(af1av{i,1});
end
Walter Roberson
Walter Roberson 2018-8-11
That code relies upon the fields all being the same datatype and all scalars (either numeric scalars or scalar logical or scalar character or scalar cell array.)

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