MATLAB如何使用查找功能与IF语句

如何使用FIND功能与IF声明这个问题是关系到How can I merge this data in MATLAB?MATLAB如何使用查找功能与IF语句

？例如如果我有这样的数据：

规则1：第3列的数据必须是1

规则2：如果n是塔1的当前索引，如果n等于n-1（20 = 20），索引n的列2的数据和n-1 被合并。

编辑：

fid=fopen('data.txt'); 
A=textscan(fid,'%f%f%f'); 
fclose(fid); 
in = cell2mat(A)'; %'# fix for SO formatting - Jonas 

%# rows2mergeFrom are the rows where the second row equals the first row of col 1 
%# and where the third column is 1. rows2mergeInto indicates the rows from which the 
%# values of the following rows should be added 
rows2mergeFrom = find(in(2:end,1) == in(1:end-1,1) & in(2:end,3) == 1) + 1; 

out = in; 
out(rows2mergeFrom-1,2) = out(rows2mergeFrom-1,2) + out(rows2mergeFrom,2); 

%# data that has been shifted up gets subtracted from the 'rows2mergeFrom'-rows 
out(rows2mergeFrom,2) = out(rows2mergeFrom,2) - in(rows2mergeFrom,2); 

%# remove the ones in the third column from any row that has been involved in a 
%# merge operation 
out([rows2mergeFrom;rows2mergeFrom-1],3) = 0 

fid = fopen('newData.txt','wt'); 
format short g; 
fprintf(fid,'%g\t %g\t %g\n',out); %'# Write the data to the file 
fclose(fid);

来源

2010-06-20 Jessy

结果与您所描述的不一致！ – Amro 2010-06-20 19:19:25

我认为数组应该是26，而不是25，在位置'（2,2）' – Jonas 2010-06-20 19:48:02

我已经改变了输出 – Jessy 2010-06-20 20:03:58

没有必要的if语句。你需要的是一个逻辑数组，允许find提取要合并的行的行索引。

更新至于我可以告诉新规则

in = [20 10 1 
20 11 1 
20 15 1 
23 10 1 
23 10 1 
23 12 0]; 

%# rows2mergeFrom are the rows where the second row equals the first row of col 1 
%# and where the third column is 1. rows2mergeInto indicates the rows from which the 
%# values of the following rows should be added 
rows2mergeFrom = find(in(2:end,1) == in(1:end-1,1) & in(2:end,3) == 1) + 1; 

out = in; 
out(rows2mergeFrom-1,2) = out(rows2mergeFrom-1,2) + out(rows2mergeFrom,2); 

%# data that has been shifted up gets subtracted from the 'rows2mergeFrom'-rows 
out(rows2mergeFrom,2) = out(rows2mergeFrom,2) - in(rows2mergeFrom,2); 

%# remove the ones in the third column from any row that has been involved in a 
%# merge operation 
out([rows2mergeFrom;rows2mergeFrom-1],3) = 0 

out = 
20 21  0 
20 15  0 
20  0  0 
23 20  0 
23  0  0 
23 12  0

来源

2010-06-20 19:43:23 Jonas

符合，你不需要使用查找或如果。你只需要逻辑索引。

如果我正确理解您的问题，Amro正确地指出您的输出与您的逻辑描述不符。请尝试以下脚本：

m = [20 10 0; ... 
    20 11 0; ... 
    20 15 1; ... 
    23 10 1; ... 
    23 10 1]; 
merge = (m(1:end-1, 1) == m(2:end, 1)) & (m(2:end,3) == 1) 
mnew = m(2:end, :); 
madd = m(1:end-1,2) + m(2:end,2); 
mnew(merge, 2) = madd(merge); 
mnew = [m(1,:); mnew]

来源

2010-06-20 19:46:25 Reinderien

MATLAB如何使用查找功能与IF语句

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