在MATLAB中从稀疏矩阵中提取列向量？

I am new to MATLAB.

我是MATLAB的新手。

I have a sparse matrix (2649429x148) which I got through spconvert function. It is a sparse user-movie matrix. I want to get all the ratings for a particular movie. The user-id space has some gaps and is not continuous.

我有一个稀疏矩阵（2649429x148），我通过spconvert函数。它是一个稀疏的用户电影矩阵。我希望获得特定电影的所有评分。用户ID空间有一些间隙，不连续。

I tried the following

我尝试了以下内容

 mat     
            (967,1)                       1
           (7798,1)                       4
          (16272,1)                       2
          (21722,1)                       3
             .
             .
             .
          (11,148)                        5
          (2342432,148)                   5
          (2332332,148)                   5

 mat(:,4)      % it get the following 

            (967,1)                       1
           (7798,1)                       4
          (16272,1)                       2
          (21722,1)                       3
          (42773,1)                       3
          (48286,1)                       5
          (98649,1)                       2
         (156319,1)                       2
         (165720,1)                       2
          .........

I want to get (xxxxxx, 4) .....

我想得到（xxxxxx，4）.....

How can I get a column vector of all the ratings for a particular movie?

如何获取特定电影的所有评级的列向量？

1 个解决方案

#1

Check this out if it works -

检查一下它是否有效 -

[~,col1,val] = find(mat);
ratings = val(col1==4)