Changing properties of a Javascript object from string to int

问题

I have an array of objects with three properties each (year, total, per_capita). Example:

0: Object
  per_capita: "125.8"
  total: "1007.2"
  year: "2009"

Those properties are strings and I want to create a loop that goes through the array and converts them to int. I tried the following loop:

for (i=0; i<data.length; i++){
    parseInt(data[i].year, 10)
    parseInt(data[i].total, 10)
    parseInt(data[i].per_capita, 10)
}

However when I do typeof(data[0].total) it says its a string. I am having problems later in the program and I think it is because the values cannot be computed properly because they are not the right type. Anyone have an idea where the problem is?

回答1:

parseInt does not mutate objects but parses a string and returns a integer. You have to re-assign the parsed values back to the object properties.

for (i=0; i<data.length; i++){
    data[i].year = parseInt(data[i].year, 10)
    data[i].total = parseInt(data[i].total, 10)
    data[i].per_capita = parseInt(data[i].per_capita, 10)
}

回答2:

This should help!

var a = {
  per_capita: "125.8",
  total: "1007.2",
  year: "2009",
}

Object.keys(a).forEach(function(el){
  a[el] = parseInt(a[el])
})

console.log(a)
console.log(typeof a.total)

回答3:

All you did was the conversion, but you missed the assignment:

for (i=0; i<data.length; i++){
    data[i].year = parseInt(data[i].year, 10)
    data[i].total = parseInt(data[i].total, 10)
    data[i].per_capita = parseInt(data[i].per_capita, 10)
}

The parseInt function returns the int value, it doesn't change the input variable.

Another thing - if you need the total number to be float you should use the parseFloat function and not the parseInt.

回答4:

You could iterate the array and the object amd assign the integer value of the properties, you want.

data.forEach(function (a) {
    ['year', 'total', 'per_capita'].forEach(function (k) {
        a[k] = Math.floor(+a[k]);
    });
});

来源：https://stackoverflow.com/questions/39836839/changing-properties-of-a-javascript-object-from-string-to-int

标签

javascript

arrays

object

parseint