WMLScript » Lang » Lang.parseFloat
- Syntax:
- Lang.parseFloat(value)
- value
- The mandatory value parameter can be any string that begins with numeric characters, or begins with a plus or minus sign followed by numeric characters. Your string can also contain exponential designation.
Converts a string into a floating-point number.
The
Lang.parseFloat function converts the given string value into a
floating-point number.
The function parses the
string value until the end is reached or the first invalid character is
encountered. If the very first character is not a digit, a plus + sign,
or a negative - sign, then an invalid is returned. Also, if an
error occurs, invalid is returned. The parsing recognizes the
use of exponential designation, such as 94.375e3.
The browser must recognize floating-point numbers. You
can test for this by using the Lang.float function.
You can also use the Lang.isFloat function to
test a string to pre-determine if it can be converted into a
floating-point number. This can prevent invalid from being
returned.
Here are the
results of some conversions:
| Value | Return |
| "101" | 101.0 |
| "-101" | -101.0 |
| "984.653" | 984.653 |
| "42 feet" | 42.0 |
| "7 inches by 8 inches" | 7.0 |
| "75e3" | 75000.0 |
| "83.67e-9" | 83.67e-9 |
| "$12.99" | invalid |
| "The size is 4x8 feet" | invalid |
Examples
Code:
<?xml
version="1.0"?>
<!DOCTYPE wml PUBLIC "-//WAPFORUM//DTD
WML 1.1//EN"
"http://www.WAPforum.org/DTD/wml_1.1.xml">
<wml>
<card id="card1">
<p>
parseFloat
example
</p>
<do type="accept">
<go
href="ParseFloatExample.wmls#findparsefloat()" />
</do>
</card>
<card id="card2">
<p>
float number = $(floatnumber)
</p>
</card>
</wml>Explanation:
Code for ParseFloatExample.wml
Language(s): WML
Code:
extern function findparsefloat()
{
var result = Dialogs.prompt("Enter number",
"");
var test =
Lang.isFloat(result);
if(test ==
true)
{
var floatnum = Lang.parseFloat(result);
WMLBrowser.setVar("floatnumber",
floatnum);
WMLBrowser.go("ParseFloatExample.wml#card2");
}
else
{
WMLBrowser.setVar("floatnumber",
test);
WMLBrowser.go("ParseFloatExample.wml#card2");
}
};
Explanation:
In this example, if the string can be converted to floating-point, the converted number is returned. If the string cannot be converted, false is returned.
Language(s): WML
See Also:
