Need to convert char to struct

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.

Answer 1

[Walter Roberson]

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.

[Paul]

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]

ewa2 = regexp(ewa, ',\s*', 'split');
ewa3 = str2double(ewa2);

[Paul]

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

Answer 2

[Azzi Abdelmalek]

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

[Paul]

    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]

a=regexp(ewa,'[^,\s]+','match')
str=reshape(str,2,[])'
dates=str(2:end,1)
price=str2double(str(2:end,2))

[Image Analyst]

I think you mean "dates" since date is the name of a built in function.

[Azzi Abdelmalek]

Exact