Need to convert char to struct

2014 4 13
2 个回答
更新时间：2014 4 13
10 次查看（30 天）

0 个投票

I am trying to use a trading algorithm and I need to check prices daily. I can download the prices manually and load them into matlab manually, but I don't want to do that every single day. I get the data from quandl.com and when I use urlread on the data file, it returns a char of the data with each value separated with a comma. How can I convert this to a structured array in my program? Should I be using a different command besides urlread for this? I've tried using struct() on the char variable but is doesn't work.

请先登录，再回答此问题。

回答（2 个）

Walter Roberson
Walter Roberson 2014-4-13

0 个投票

I recommend using regexp() with the 'split' option to get the text for each number into its own cell array entry, and then str2double() the overall cell array to get the numeric values. Or if you know exactly how many data values are expected, you could sscanf() on the strings.

3 个评论
显示 1更早的评论 隐藏 1更早的评论

Paul
Paul 2014-4-13
Is this right?
ewa2 = regexp(ewa, 'split'); ewa3 = str2double(ewa2);
"ewa" is my char variable. The code above returns ewa2 as empty and ewa3 as nan.
Walter Roberson
Walter Roberson 2014-4-13
ewa2 = regexp(ewa, ',\s*', 'split');
ewa3 = str2double(ewa2);
Paul
Paul 2014-4-13
ewa = urlread('http://www.quandl.com/api/v1/datasets/GOOG/NYSEARCA_EWA.csv?column=4');
ewa2 = regexp(ewa, ',\s*', 'split');
ewa3 = str2double(ewa2);
This gives me a 1 x 4098 double of NaN's as ewa3. You can look at the data I'm dealing with by opening the link: http://www.quandl.com/api/v1/datasets/GOOG/NYSEARCA_EWA.csv?column=4

请先登录，再进行评论。

Azzi Abdelmalek
Azzi Abdelmalek 2014-4-13

0 个投票

str='12.03,23,25,26,30'
a=struct('data',num2cell(str2double(regexp(str,'[\w\.]+','match'))))

4 个评论
显示 2更早的评论 隐藏 2更早的评论

Paul
Paul 2014-4-13
ewa = urlread('http://www.quandl.com/api/v1/datasets/GOOG/NYSEARCA_EWA.csv?column=4');
ewa2=struct('data',num2cell(str2double(regexp(ewa,'[\w\.]+','match'))))
This woudld work, but for some reason it not only seperates at commas, but also at hyphens, which seperates the dates, which look like this: 2014-4-11
Azzi Abdelmalek
Azzi Abdelmalek 2014-4-13
编辑：Azzi Abdelmalek 2014-4-13
a=regexp(ewa,'[^,\s]+','match')
str=reshape(str,2,[])'
dates=str(2:end,1)
price=str2double(str(2:end,2))
Image Analyst
Image Analyst 2014-4-13
I think you mean "dates" since date is the name of a built in function.

请先登录，再进行评论。

类别

在 帮助中心 和 File Exchange 中查找有关 Data Type Conversion 的更多信息

标签

尚未输入任何标签。

提问:

Paul
Paul
2014-4-13

评论：

Azzi Abdelmalek
Azzi Abdelmalek
2014-4-13

Community Treasure Hunt

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

Start Hunting!

Translated by