urlread function: put variable in string

I am using the urlread() function to read in information from an url. How could I include variables into the url address?

I have latitude and longitude information which I would like to implement into the url when looping through the data. Here some example for lat and long variables:

lat=43.2;
long=116.3

I tried using num2str(variablename) but this failed with an unexpected matlab error

alt= urlread('http://api.geonames.org/astergdem?lat=' num2string(lat) '&lng=' num2str(long) '&username=test12345&style=full&type=JSON')

Answer 1

[Cedric]

You can concatenate strings using square brackets, but I usually prefer building a final string using SPRINTF, e.g.

 url = sprintf( 'http://api.geonames.org/astergdem?lat=%f&lng=%f&username=test12345&style=full&type=JSON', lat, long ) ;
 data = urlread( url ) ;

The first string in the call to SPRINTF is called formatSpec. Look in MATLAB doc and you will see what the two %f stand for and how to tailor them to your needs. In your command window, type

 doc sprintf

and look for the formatSpec.