MATLAB如何在IF语句中使用FIND函数
 

这个问题与[URL="https://stackoverflow.com/questions/3071558/matlab-how-to-merge-data"]我如何在MATLAB中合并这些数据有关？[/URL]

如何在IF语句中使用FIND函数？例如，如果我有此数据：

20 10 1 20 11 1 20 15 1 23 10 1 23 10 1 23 12 0 规则1：第3列的数据必须为1。

规则2：如果n是第1列的当前索引，则如果n等于n-1列的n-1 （20 = 20），则将索引n和n-1的第2列的数据[B]合并。[/B]

20 21 0 20 15 0 20 0 0 23 20 0 23 0 0 23 12 0 [B]编辑：[/B]

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);

[B]回答：[/B]

无需if语句。您需要一个逻辑数组，该数组允许find提取要合并的行的行索引。

[B]更新以符合新规则[/B]

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

[url=https://stackoverflow.com/questions/3080120]更多&回答...[/url]