How to use webread with a variable (from a table) in the url

Question

Benjamin Lepage 2020-4-6

0
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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/515710-how-to-use-webread-with-a-variable-from-a-table-in-the-url

编辑： Geoff Hayes 2020-4-6

采纳的回答： Geoff Hayes

在 MATLAB Online 中打开

Hello,

I'm trying to create a map of temperature evolution over time in the world.

So i need to get api data from each country and i would like to have this kind of url: http://climatedataapi.worldbank.org/climateweb/rest/v1/country/annualavg/tas/1980/1999/FRA

clear
data = readtable('countries_codes_and_coordinates.csv'); 
code = data(76,3); % code = 'FRA'
url = sprintf( 'http://climatedataapi.worldbank.org/climateweb/rest/v1/country/annualavg/tas/1980/1999/', code ) ;
FRANCE = webread( url ) ;

But when I run the code I get an error..

Error in readContentFromWebService (line 46)
        byteArray = copyContentToByteArray(connection);
Error in webread (line 125)
[varargout{1:nargout}] = readContentFromWebService(connection, options);
Error in Projet (line 8)
FRANCE = webread( url ) ;

Do you know why my code is false? I also want to remove '...' from 'FRA' because it's probably also an error.

Thanks in advance

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Answer 1

Geoff Hayes 2020-4-6

2
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此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/515710-how-to-use-webread-with-a-variable-from-a-table-in-the-url#answer_424380

编辑：Geoff Hayes 2020-4-6

在 MATLAB Online 中打开

Benjamin - you need to specify a format when using sprintf so that the code is included in the string. For example,

>> code = 'FRA'; % code = 'FRA'
>> url = sprintf( 'http://climatedataapi.worldbank.org/climateweb/rest/v1/country/annualavg/tas/1980/1999/', code);
>> url
url =
http://climatedataapi.worldbank.org/climateweb/rest/v1/country/annualavg/tas/1980/1999

and note how url does not have the FRA country included..because we didn't "tell" sprintf about it. Since code is a string, we need to include the %s to indicate where it should "fit" in the URL:

>> code = 'FRA'; % code = 'FRA'
>> url = sprintf( 'http://climatedataapi.worldbank.org/climateweb/rest/v1/country/annualavg/tas/1980/1999/%s', code);
>> url
url =
http://climatedataapi.worldbank.org/climateweb/rest/v1/country/annualavg/tas/1980/1999/FRA