How would I access certain elements from object from an array list?
Say I have an array:
var test = [{"a":1, "b":2, "c":3}, {"a":4, "b":5, "c":6}];
I know that test[1] will output {"a":4, "b":5, "c":6"}.
And test[1].b will output 5
How can I output {"b":2, "c":3"}, {"b":5, "c":6"} without using a for loop?
If you want to return a copy of the original array without "a" property this would work:
text.map((el)=> {
delete el.a
return el
})
text array will also have the a property deleted.
var res = text.map((el)=> Object.assign({}, {b:el.b, c:el.c})You can do like this :
text.forEach(function(row){
delete row.a;
});
It will delete 'a' property from list of text's row.
Filter is the wrong tool. If you don't want to modify the original array, you can map it to a new array containing copies of the original elements with the "a" property deleted.
var text = [{"a":1, "b":2, "c":3}, {"a":4, "b":5, "c":6}];
var result = text.map(
function(elt) {
var copy = Object.assign({}, elt);
delete copy.a;
return copy;
}
)
As a learning exercise you could use map to create an array of new objects which contain copies of the "b" and "c" properties found in input array elements. This example uses destructuring asignment syntax in the mapping function.
var array1 = [{"a":1, "b":2, "c":"3"}, {"a":4, "b":5, "c":6}];
var array2 = array1.map( obj => {var {b,c} = obj; return {b,c};});
// check output
console.log (JSON.stringify( array2)) // [{"b":2,"c":"3"},{"b":5,"c":6}]Note that when copying objects or arrays of objects in JavaScript, what needs to be copied and whether object references can be copied unchanged needs to be identified first. So, if you needed to copy all properties except for the "a" property, this answer would need to be modified.
You've got 2 options: iterate over the array using the delete operator:
var text = [{"a":1, "b":2, "c":3}, {"a":4, "b":5, "c":6}];
text.forEach(function(obj) {
delete obj.a;
});
console.log(text);Or create a copy of the objects that have all but the a property:
var text = [{"a":1, "b":2, "c":3}, {"a":4, "b":5, "c":6}];
var newText = text.map(function(obj) {
var newObj = {};
for (var prop in obj) {
if (prop !== 'a') {
newObj[prop] = obj[prop];
}
}
return newObj;
});
console.log(newText);
afrom both the objects and then log it?