how to Vectorize this for loop
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Hi everyone i have wrote this code and i want to vectorize my code so it run faster here is the part of code i'm talking about
fileID = fopen('CANDec(day_1_9).txt','r');
text_data = textscan(fileID,'%s %s %s %s %s %s %s %s',1000,'delimiter',';');
hex=text_data(:,4);
signal_name=text_data(:,7);
decimal_wert=text_data(:,8);
for i =1:length(text_data{1,1})
can.(signal_name{1,1}{i,1}).hex{i,1}=hex{1,1}{i,1};
can.(signal_name{1,1}{i,1}).decimal_wert{i,1}=decimal_wert{1,1}{i,1};
end
hex , signal_name and decimal_wert are cells that i read from a .txt file (CANDec(day_1_9)). it has actually many million lines . it's means there is millions of signal_name but here i read just 1000 lines.
now i'm building a structure can and as the name for substructures i use signal_name dynamically. if you go in can-structure you see all signal_name as substructure and in these substruct you find again 2 substruct with the names hex and decimal_wer.
i hope you understand the code . so my goal is to vectorize this for loop . when i remove the for and vectorize it simply I will get this error :
Expected one output from a curly brace or dot indexing expression, but there were 1000 results.
i =1:length(text_data{1,1})
can.(signal_name{1,1}{i,1}).hex{i,1}=hex{1,1}{i,1};
can.(signal_name{1,1}{i,1}).decimal_wert{i,1}=decimal_wert{1,1}{i,1};
i hope you can help me with that.
Thank you
采纳的回答
Try doing something like this:
[fid,msg] = fopen('CANDec(day_1_9).txt','rt');
assert(fid>=3,msg) % good practice to check the FID.
C = textscan(fileID,'%s%s%s%s%s%s%s%s',1000,'delimiter',';');
fclose(fid);
% Simpler to get the CONTENTS of the cell array:
hx = C{4}; % hex
sn = C{7}; % signal name
dw = C{8}; % decimal wert
I strongly recommend that you do not use nested structures, but instead store the signal name as data in its own right in a non-scalar structure, then your task is trivial:
can = struct('signalName',sn, 'hex',hx, 'decimalWert',dw)
And you can access the data in can using some very convenient sytaxes:
5 个评论
Milad Ghobadi
2020-2-14
编辑：Milad Ghobadi
2020-2-14
"I hope i could find a solution for this "
You would need to use loop, which is why accessing data in nested structures is usually not very convenient.
But what you show does not require nested structures, it would be much simpler to generate and access using a non-scalar structure:
can(1).hex = {'AB','1DFA'};
can(1).name = 'signal_1';
can(2).hex = {'A2', '1DFA', '1235'};
can(2).name = 'signal_2';
...
Milad Ghobadi
2020-2-14
编辑：Milad Ghobadi
2020-2-14
sn = { 'B_UF'; 'B_IN'; 'B_UF'; 'B_UF'; 'B_STMAX'; 'B_STMAX'};
hx = { '374C'; '025A'; '00'; 'BB'; 'AA'; 'F9'};
dw = {'704.17';'29.94'; '0'; '1234'; '0'; '249.0'};
[fn,~,ix] = unique(sn);
Using nested structures:
can = struct();
for k = 1:max(ix)
can.(fn{k}).hex = hx(k==ix);
can.(fn{k}).dWt = dw(k==ix);
end
Checking:
>> can.B_UF.hex
ans =
'374C'
'00'
'BB'
Or with a non-scalar structure:
can = struct();
for k = 1:max(ix)
can(k).name = fn{k};
can(k).hex = hx(k==ix);
can(k).dWt = dw(k==ix);
end
Checking:
>> can(3).name
ans =
B_UF
>> can(3).hex
ans =
'374C'
'00'
'BB'
I strongly recommend that you use a non-scalar structure. As well as the ease of access, consider what your code would do if one of the signal_names is not a valid fieldname.
Milad Ghobadi
2020-2-17
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