Check if URL exists

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Ryan 2012-7-30

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编辑： Walter Roberson 2017-4-26

Does anyone know how to check if a URL exists? The function exist seems to only work of file paths through a computer.

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Walter Roberson 2012-7-30

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https://ww2.mathworks.cn/matlabcentral/answers/44886-check-if-url-exists#answer_54988

It is possible to detect that a URL does exist, but it is not always possible to detect that a URL does not exist compared to it existing but you not being permitted to examine it.

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Edward Strobach 2017-4-25

@Walter, that first response was deep

Edward Strobach 2017-4-26

编辑：Walter Roberson 2017-4-26

在 MATLAB Online 中打开

I found for files online, that I can create a function that examines, iteratively, the presence of a file within a URL to determine whether or not it exists.

Example

function [info,status] = FileExists(t)
t = num2str(8965);
url = strcat('http://podaac-opendap.jpl.nasa.gov/opendap/allData/oscar/preview/L4/oscar_third_deg/oscar_vel',t,'.nc.gz');[~,status] = urlread(url);
filename = strcat('oscar_vel',t,'.nc.gz');
try 
    Info = ncinfo(url);
    status = 1;
catch 
    Info = [];
    status = 0;
end

If status is 1, then file exists, if status is 0, the file doesnt' exist. You can use a tilde for the first output within the square brackets to suppress the output if you only want to look at the status

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