用 MATLAB 读取 CSV 文件? [英] Reading CSV files with MATLAB?

问题描述

我正在尝试使用 MATLAB 读取 .csv 文件.这是我的代码:

I am trying to read in a .csv file with MATLAB. Here is my code:

csvread('out2.csv')

这是 out2.csv 的样子:

This is what out2.csv looks like:

03/09/2013 23:55:12,129.32,129.33
03/09/2013 23:55:52,129.32,129.33
03/09/2013 23:56:02,129.32,129.33

在 Windows 上，我可以使用 xlsread 函数读取这个完全相同的文件，没有任何问题.我目前在一台 linux 机器上.当我第一次使用 xlsread 读取文件时，我被告知文件不是可识别的格式"，所以我改用 csvread.但是，使用 csvread，我收到以下错误消息:

On windows I am able to read this exact same file with the xlsread function with no problems. I am currently on a linux machine. When I first used xlsread to read the file I was told "File is not in recognized format" so I switched to using csvread. However, using csvread, I get the following error message:

Error using dlmread (line 139)
Mismatch between file and format string.
Trouble reading number from file (row 1u, field 2u) ==> /09/2013
23:55:12,129.32,129.33


Error in csvread (line 48)
m=dlmread(filename, ',', r, c)

我认为日期中的/"是导致问题的原因.在 Windows 上，第一列被解释为字符串.在 linux 上，它似乎被解释为一个数字，因此它尝试读取该数字并在反斜杠处失败.这就是我认为至少正在发生的事情.任何帮助将不胜感激.

I think the '/' in the date is causing the issue. On windows, the 1st column is interpreted as a string. On linux it seems to be interpreted as a number, so it tries to read the number and fails at the backslash. This is what I think is going on at least. Any help would be really appreciated.

推荐答案

csvread 只能读取双打，所以在日期字段卡住了.使用 textscan.

csvread can only read doubles, so it's choking on the date field. Use textscan.

fid = fopen('out2.csv');
out = textscan(fid,'%s%f%f','delimiter',',');
fclose(fid);

date = datevec(out{1});
col1 = out{2};
col2 = out{3};

<小时>

更新(8/31/2017)

自从 2013 年写回，MATLAB 的 textscan 函数已更新为直接读取日期和时间.现在代码看起来像这样:

Since this was written back in 2013, MATLAB's textscan function has been updated to directly read dates and times. Now the code would look like this:

fid = fopen('out2.csv');
out = textscan(fid, '%{MM/dd/uu HH:mm:ss}D%f%f', 'delimiter', ',');
fclose(fid)

[date, col1, col2] = deal(out{:});

下面@Victor Hugo 提到的另一种选择(目前我个人对这种情况的首选)是使用 readtable 它将接受与 textscan 相同的格式化字符串，但将结果直接组合成一个表格对象:

An alternative as mentioned by @Victor Hugo below (and currently my personal go-to for this type of situation) would be to use readtable which will accept the same formatting string as textscan but assemble the results directly into a table object:

dataTable = readtable('out2.csv', 'Format', '%{MM/dd/uu HH:mm:ss}D%f%f')
dataTable.Properties.VariableNames = {'date', 'col1', 'col2'};

dataTable =

  3×3 table

           date             col1      col2 
    ___________________    ______    ______

    03/09/2013 23:55:12    129.32    129.33
    03/09/2013 23:55:52    129.32    129.33
    03/09/2013 23:56:02    129.32    129.33

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