javascript parse number

How can I convert a string to an integer in JavaScript?

stackoverflow.com › questions › 1133770 › how-can-i-convert-a-string-to-an-integer-in-javascript

The simplest way would be to use the native Number function:

var x = Number("1000")

If that doesn't work for you, then there are the parseInt, unary plus, parseFloat with floor, and Math.round methods.

parseInt()

var x = parseInt("1000", 10); // You want to use radix 10
    // So you get a decimal number even with a leading 0 and an old browser ([IE8, Firefox 20, Chrome 22 and older][1])

Unary plus

If your string is already in the form of an integer:

var x = +"1000";

floor()

If your string is or might be a float and you want an integer:

var x = Math.floor("1000.01"); // floor() automatically converts string to number

Or, if you're going to be using Math.floor several times:

var floor = Math.floor;
var x = floor("1000.01");

parseFloat()

If you're the type who forgets to put the radix in when you call parseInt, you can use parseFloat and round it however you like. Here I use floor.

var floor = Math.floor;
var x = floor(parseFloat("1000.01"));

round()

Interestingly, Math.round (like Math.floor) will do a string to number conversion, so if you want the number rounded (or if you have an integer in the string), this is a great way, maybe my favorite:

var round = Math.round;
var x = round("1000"); // Equivalent to round("1000", 0)

Answer from Nosredna on Stack Overflow

MDN Web Docs

developer.mozilla.org › en-US › docs › Web › JavaScript › Reference › Global_Objects › parseInt

parseInt() - JavaScript | MDN

The parseInt function converts its first argument to a string, parses that string, then returns an integer or NaN. If not NaN, the return value will be the integer that is the first argument taken as a number in the specified radix. (For example, a radix of 10 converts from a decimal number, ...

Stack Overflow

stackoverflow.com › questions › 1133770 › how-can-i-convert-a-string-to-an-integer-in-javascript

How can I convert a string to an integer in JavaScript? - Stack Overflow

parseInt()

var x = parseInt("1000", 10); // You want to use radix 10
    // So you get a decimal number even with a leading 0 and an old browser ([IE8, Firefox 20, Chrome 22 and older][1])

Unary plus

If your string is already in the form of an integer:

var x = +"1000";

floor()

If your string is or might be a float and you want an integer:

var x = Math.floor("1000.01"); // floor() automatically converts string to number

Or, if you're going to be using Math.floor several times:

var floor = Math.floor;
var x = floor("1000.01");

parseFloat()

If you're the type who forgets to put the radix in when you call parseInt, you can use parseFloat and round it however you like. Here I use floor.

var floor = Math.floor;
var x = floor(parseFloat("1000.01"));

round()

Interestingly, Math.round (like Math.floor) will do a string to number conversion, so if you want the number rounded (or if you have an integer in the string), this is a great way, maybe my favorite:

var round = Math.round;
var x = round("1000"); // Equivalent to round("1000", 0)

2 of 16

306

Try parseInt function:

var number = parseInt("10");

But there is a problem. If you try to convert "010" using parseInt function, it detects as octal number, and will return number 8. So, you need to specify a radix (from 2 to 36). In this case base 10.

parseInt(string, radix)

Example:

var result = parseInt("010", 10) == 10; // Returns true

var result = parseInt("010") == 10; // Returns false

Note that parseInt ignores bad data after parsing anything valid.
This guid will parse as 51:

var result = parseInt('51e3daf6-b521-446a-9f5b-a1bb4d8bac36', 10) == 51; // Returns true

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