read a range of values using dlmread

4 次查看（过去 30 天）
Costanzo
Costanzo 2012-10-15
回答： Supreeth Subbaraya 2014-8-4
Hi everybody,
I am using dlmwrite to write a vector into a .csv file. Then I would like to read only a certain range of this vector with dlmread. This is an example of my code:
% file tries.m
mins = 20; % length of recording in minutes
Fs = 512; % sample rate
a = zeros (1, mins*60*Fs); % create fake vector
dlmwrite ( 'data_raw.csv', a ); % write vector to csv file
v1 = dlmread ( 'data_raw.csv', ',', [0 0 mins*60*Fs-1 0] ); % read whole vector
v2 = dlmread ( 'data_raw.csv', ',', [1 0 mins*60*Fs-1 0] ); % read roffset = 1
When I read the whole vector (in v1) everything is fine. When I try to read starting from position 1 (in v2), I receive the following error:
Error using dlmread (line 139)
Badly formed format string.
Error in tries (line 8)
v2 = dlmread ( 'data_raw.csv', ',', [1 0 mins*60*Fs-1 0] );
Has anybody got any idea why this is happening? How can I successfully read only a range of values from the csv file?
Thank you very much, Costanzo

请先登录，再回答此问题。

回答（1 个）

Supreeth Subbaraya
The "a" vector is exceeding in the number of columns a csv file can hold. You can store the vector as a column vector as opposed to a row vector in the csv and access it. To do this, write to the csv file as
>> dlmwrite('data_raw.csv',a').
Then you can access the values as given in the documentation here.
Also, you can consider the function csvread for reading and writing csv files. Documentation is available here

类别

在 Help Center 和 File Exchange 中查找有关 Text Files 的更多信息

标签

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by