String to Int (number)

Question

Possible Duplicate:
How do I Convert a String into an Integer in JavaScript?

i have the following code:

    $.ajax({
      type: "GET",
      url: 'index.php?act=ajax&op=getShippingPrice&id='+shippingID,
      success: function(data) {
        var currentPrice = Number($("#finalPrice").html());
        var newPrice = Number(currentPrice + data);
        $("#finalPrice").html(newPrice);
      }
    });

i try to calculate the new price. but i actually get a string of newPrice, which contains the current price, and right after it the data from ajax.

if the current price is 1500, and data from ajax is 10, what i get is 150010, and not 1510.

i also tried to use parseInt, probably didn't use it right.

Yes, it's most likely `$('#finalPrice').html()` which outputs a string, instead of an int, using `parseInt` will cast the string to an integer, and instead of the `+` operator `concatenating` a string, it will `add` to the integer. — Ohgodwhy, Jan 03 '13 at 08:42
Both operands need to be numbers if you want to perform addition. — Felix Kling, Jan 03 '13 at 08:43

ATOzTOA · Answer 1 · 2013-01-03T10:45:19.710

4

Use this:

Assuming a price with decimals, using parseFloat, if not, use parseInt.

$.ajax({
  type: "GET",
  url: 'index.php?act=ajax&op=getShippingPrice&id='+shippingID,
  success: function(data) {
    var currentPrice = parseFloat($("#finalPrice").html());
    var newPrice = currentPrice + parseFloat(data));
    $("#finalPrice").html(newPrice.toFixed(2));
  }
});

edited Jan 03 '13 at 10:45

answered Jan 03 '13 at 08:41

ATOzTOA

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And now a toFixed and we are there – mplungjan Jan 03 '13 at 08:45
@mplungjan IMHO you yourself are making far too many assumptions about the OP's requirements. He said he tried `parseInt` so it's reasonable to expect that the fields are actually ints, at which point use of `parseFloat` and `toFixed` are inappropriate. – Alnitak Jan 03 '13 at 09:12
1

Inappropriate is a hard word to use when the thing is a price. It could be added to this solution that "Assuming a price with decimals, use parseFloat, if not, use parseInt" and that would handle any assumptions. – mplungjan Jan 03 '13 at 09:19

score 2 · Answer 2 · answered Jan 03 '13 at 08:41

2

Do it like:

var newPrice = parseInt(currentPrice) + parseInt(data);

answered Jan 03 '13 at 08:41

Arvind Bhardwaj

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bumerang · Answer 3 · 2013-01-03T09:00:39.000

0

This will help You:

 var newPrice = 1*currentPrice + 1*data;

Multiply by 1 don't change the result but it will change the variable type.

edited Jan 03 '13 at 09:00

answered Jan 03 '13 at 08:42

bumerang

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1

There are built in functions to do this! – mplungjan Jan 03 '13 at 08:44
Yes but there is no reason to take canon to shut sparrow :) – bumerang Jan 03 '13 at 08:46
And You don't even need `Number` function after that. – bumerang Jan 03 '13 at 08:47
You have a totally unnecessary Number in there but that is ok? (And it is cannon and shoot) – mplungjan Jan 03 '13 at 08:47
1

in any event the canonical "short" way to convert a variable to a floating point number (without error checking) is to use `+currentPrice`, not `1 * ...` – Alnitak Jan 03 '13 at 08:49
Yes Your right, that's why I have write it's unnecessary right before You. It can be `var newPrice = 1*currentPrice + 1*data;` – bumerang Jan 03 '13 at 08:51
So update your answer... – mplungjan Jan 03 '13 at 08:55

score 0 · Answer 4 · answered Jan 03 '13 at 08:42

0

Convert your HTML-derived value into a number first (and ensure you supply the radix parameter to cope with leading zeroes).

You should also remove any white space that might exist:

var currentPrice = parseInt($.trim($("#finalPrice").html()), 10);
var newPrice = currentPrice + data;

If the output from the server is not in JSON format then you should also convert the data field too before the addition:

data = parseInt(data, 10);

Finally, if your numbers aren't actually integers, use parseFloat instead of parseInt

answered Jan 03 '13 at 08:42

Alnitak

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Data will surely be a string – mplungjan Jan 03 '13 at 08:43
@mplungjan not if the response is JSON - the OP didn't say. – Alnitak Jan 03 '13 at 08:44
I would NEVER trust it to be numeric – mplungjan Jan 03 '13 at 08:46
A bare number returned in an HTTP response is legal JSON, so the parsing would depend on the `Content-Type` header. – Alnitak Jan 03 '13 at 08:47
I could see a space break that... – mplungjan Jan 03 '13 at 08:49
@mplungjan yes, a space from the server _could_ break that, but without information from the OP about whether his output is "plain ASCII" or "JSON" you're just picking nits. – Alnitak Jan 03 '13 at 08:50
Or introducing OP to defensive coding :) – mplungjan Jan 03 '13 at 08:56
The defensive bit is the trim call for the contents of the HTML DOM. It shouldn't be necessary to "defend" against a server sending valid JSON. If the JSON isn't valid, it won't even reach this code. – Alnitak Jan 03 '13 at 09:13

score -1 · Answer 5 · answered Jan 03 '13 at 08:43

-1

Try modifying like this one:

$.ajax({ type: "GET", url: 'index.php?act=ajax&op=getShippingPrice&id='+shippingID, success: function(data) {

    var newPrice = Number(currentPrice + Number($("#finalPrice").html()));
    $("#finalPrice").html(newPrice);
  }
});

At least you will get error.

answered Jan 03 '13 at 08:43

Sarang

171
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Why wrap numbers in number? – mplungjan Jan 03 '13 at 08:43

String to Int (number)

5 Answers5