I have a JSON object of arrays
data = {
China: ["Guangzhou","Fax"],
Majorette: ["Fungous","Godzilla"],
Bhutan: ["Thimphu","Parr","Photofinishing"]
}
I want to access name of cities in an array without explicitly mentioning the name of countries as list is very long.
var cities = [];
for(var i in data.China) {
cities[i] = data.China[i];
}
How should I do for all the countries?
This should populate the cities array:
var data = {
China: ["Guangzhou","Fax"],
Majorette: ["Fungous","Godzilla"],
Bhutan: ["Thimphu","Parr","Photofinishing"]
}
var cities = [];
for(var i in data){
if(data.hasOwnProperty(i)){
for(var j in data[i] ){
if(data[i].hasOwnProperty(j)){
cities.push(data[i][j]);
}
}
}
}
console.log(cities);
[] in place of new Array and that a loop that pushes things is just a array.map..length for example. This means you should wrap that code in a hasOwnProperty check. See javascript.crockford.com/code.html
for... in loops is considered bad practice since the iteration order is not guaranteed. To be fair OP did not ask for it here so it's not a huge deal but using data[i].forEach or even better data[i].map could make your core shorter and potentially more correct.To iterate over the cities object effectively:
Object.keys(data).forEach(function(key) {
// In here, data[key] is each array of cities.
});
Now, from what I understand from your question, you want to reduce the multidimensional object/array to one flat array of cities:
var cities = Object.keys(data).reduce(function(arr, key) {
return arr.concat(data[key]);
}, []);
Please note that Object.keys, as well as Array.prototype.forEach and Array.prototype.reduce are IE9 and above functions.
for (var key in data) {
var citiesArray = data[key]; // cities for the current country
// your code
}
.length is not enumerable. That said it will count it in old browsers like IE8 for (var country in data){
for(var i=0;i<data[country].length;i++){
console.log (data[country][i]);
}
}
