Is it possible to select certain data in a JSON Object using other data in the same JSON Object. Similar to MySQL. For example:
myObj = {"elements" : [ { "name" : "Hydrogen", "symbol" : "H" }, { "name" : "Silver", "symbol" : "Ag" }]};
I want to select "Hydrogen" where the symbol is "H". Instead of having to put in something like this:
document.getElementByID("TEST").innerHTML = myObj.elements[0].name;
Thank you in advance.
You could define a function to do it for you.
document.getElementByID("TEST").innerHTML = findNameBySymbol(myObj.elements, 'H');
function findNameBySymbol(elements, symbol) {
for (var i = 0; i < elements.length; i += 1) {
if (elements[i].symbol === symbol) {
return elements[i].name;
}
}
}
Better yet, if you have any control over the structure of the data, you could structure it like this:
myObj = {"H": "Hydrogen", "Ag": "Silver"};
Then a lookup is as simple as myObj['H'].
In most cases Tyler Hoilen's solution is good enough. If you have an extremely large data, you can try to convert your data to a hash table, which would provide a fast access to the elements. Just make sure that every element has a unique symbol.
function convertToHash(data) {
var hash = {};
for (var i = 0; i < data.length; i++) {
hash[data[i].symbol] = data[i].name;
}
return hash;
}
var hash = convertToHash(myObj.elements);
document.getElementByID("TEST").innerHTML = hash["H"];
