{"id":10582,"date":"2019-03-08T09:00:24","date_gmt":"2019-03-08T14:00:24","guid":{"rendered":"https:\/\/blogs.mathworks.com\/pick\/?p=10582"},"modified":"2019-03-06T17:48:56","modified_gmt":"2019-03-06T22:48:56","slug":"world-bank-api-access","status":"publish","type":"post","link":"https:\/\/blogs.mathworks.com\/pick\/2019\/03\/08\/world-bank-api-access\/","title":{"rendered":"World Bank API Access"},"content":{"rendered":"
\n <\/p>\n

Sean<\/a>‘s pick this week is World Bank API Access<\/a> by Kim9091<\/a>.\n <\/p>\n

<\/introduction><\/p>\n

Last year, I blogged<\/a> about writing your own function signatures<\/a> for code suggestions in MATLAB. Today, I found my first instance of someone using this in the wild! And on a well documented useful tool to boot.\n <\/p>\n

Kim9091’s World Bank API takes care of making the HTTP requests to get data from the World Bank. But not only that, there’s also a live script that documents the capabilities and provides examples. Let’s give the example a whirl.\n <\/p>\n

% Make the API Connection<\/span>\r\napi = wb;\r\n\r\n% Fetch 2015 GDP Data<\/span>\r\ngdp2015 = query(api, 'source'<\/span>, '2'<\/span>, 'series'<\/span>, 'NY.GDP.PCAP.CD'<\/span>, ...<\/span>\r\n    'country'<\/span>, 'all'<\/span>, 'time'<\/span>, 'YR2015'<\/span>)<\/pre>\n
gdp2015 = \r\n  struct with fields:\r\n\r\n           page: 1\r\n          pages: 1\r\n       per_page: 9999\r\n          total: 264\r\n    lastupdated: '2019-01-30'\r\n         source: [1×1 struct]\r\n<\/pre>\n
The data comes back as a series of nested structs and cells.  To make it easier to work with, we’ll convert the struct to a table.\n   <\/p>\n
gdp2015 = struct2table(gdp2015.source.data);<\/pre>\n
Then we’ll remove all of the empty values.<\/p>\n
empties = cellfun(@isempty, gdp2015.value);\r\ngdp2015 = gdp2015(~empties, :)<\/pre>\n
gdp2015 =\r\n  248×2 table\r\n      variable         value    \r\n    ____________    ____________\r\n    [3×1 struct]    [6.4291e+03]\r\n    [3×1 struct]    [9.8352e+03]\r\n    [3×1 struct]    [1.2453e+04]\r\n    [3×1 struct]    [3.2813e+03]\r\n    ...\r\n<\/pre>\n
Since empty values were not stored as NaNs, the array was a cell.  We can now convert it to double by vertically concatenating the value of each cell.\n   <\/p>\n
gdp2015.value = vertcat(gdp2015.value{:})<\/pre>\n
gdp2015 =\r\n  248×2 table\r\n      variable        value   \r\n    ____________    __________\r\n    [3×1 struct]        6429.1\r\n    [3×1 struct]        9835.2\r\n    [3×1 struct]         12453\r\n    [3×1 struct]        3281.3\r\n    ...\r\n<\/pre>\n
And finally a plot.<\/p>\n
histogram(gdp2015.value)\r\nxlabel('GDP ($US)'<\/span>)\r\nylabel('Count'<\/span>)<\/pre>\n
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Comments<\/a><\/h3>\n
Give it a try and let us know what you think here<\/a> or leave a comment<\/a> for Kim9091.\n   <\/p>\n