如何创建循环数组

Question

I want to create a array like this:

[{'b':0,'c':1,'d':2},{'b':1,'c':2,'d':3},{'b':2,'c':3,'d':4}]

How can I do this in Javascript?

I have tried this:

for(i = 0; i < 3; i++){
    var b = i;
    var c = i+1;
    var d = i+2;
};
dataResult={"b":b,"c":c,"d":d};

alert(dataResult)  //not working result [{'b':0,'c':1,'d':2},{'b':1,'c':2,'d':3},{'b':2,'c':3,'d':4}] 

Answer 1

You are just overriding value of 'b','c','d' and at the end assigning that value to 'dataResult', so you are not getting expected result.

Try this.

 dataResult = []; for(i = 0; i < 3; i++){ dataResult.push({ 'b': i, 'c': i+1, 'd': i+2 }); }; console.log(dataResult); 

Answer 2

You'll have to create the object inside the loop, and then push it to the array:

 const arr = []; for (let i = 0; i < 3; i++) { var b = i; var c = i + 1; var d = i + 2; arr.push({ b, c, d }); } console.log(arr); 

But it would be a bit more elegant to use Array.from here:

 const arr = Array.from({ length: 3 }, (_, i) => { const b = i; const c = i + 1; const d = i + 2; return { b, c, d }; }); console.log(arr); 

Answer 3

You were creating the object outside the loop . You need to create object inside the loop .

Try following

 var arr = []; for(let i = 0; i < 3; i++){ var b = i; var c = b+1; // as b = i, you can change c = b + 1 var d = c+1; // as c = i + 1, you can change d = c + 1 arr.push({b,c,d}); }; console.log(arr); 

Answer 4

Create the object inside the loop and push it to an array

 var arr = []; for (var i = 0; i < 3; i++) { let obj = { b: i, c: i + 1, d: i + 2, } arr.push(obj) }; console.log(arr) 

Answer 5

 var myArr = []; for(var i = 0; i < 3; i++){ var data = i; myArr.push({ b: data, c: data + 1, d: data + 2 }) } console.log(myArr) 

Answer 6

You are setting the value of b, c, d after it loops so it puts the latest value of b, c, d in dataResult. Instead, you should initialize dataResult with an empty array and push values to the array after every step of the loop

var a,b,c;
var dataResult = [];
for(i = 0; i < 3; i++){
     b = i;
     c = i+1;
    d = i+2;
dataResult.push({"b":b, "c":c, "d":d});
};

alert(dataResult);