Checking Whether
the Conversion of a String into an Integer is Possible: isInt()
Function
The
isInt() function is used to
check whether the conversion of a string into an integer is possible.
The actual conversion should be done by the parseInt()
function, which will be
described in the next section.
The
syntax of isInt() is:
Lang.isInt(string);
isInt()
returns true if string
can be converted into the integer type, otherwise it returns false.
If there are any errors, the function returns invalid.
The + (optional) and -
character are used to represent positive and negative values
respectively.
The
following WMLScript example demonstrates the behavior of the isInt()
function:
u
= Lang.isInt("100"); v = Lang.isInt(" 100 "); w
= Lang.isInt("+100"); x = Lang.isInt("-100"); y
= Lang.isInt("WMLScript Tutorial"); z =
Lang.isInt(true);
After
executing the above script, the variables u
to x have the Boolean
value true while y
and z have the Boolean
value false.
Note
that if the WMLScript
interpreter encounters a non-numeric character in string,
it will check if the characters before the non-numeric character form
a valid integral value. If yes, the isInt()
function will still return true,
like this:
x
= Lang.isInt("100abc"); y = Lang.isInt("100.999"); z
= Lang.isInt(100.8);
After
the execution of the above lines of code, the variables x
to z contain the Boolean value true.
Converting a String
to an Integer: parseInt() Function
The
parseInt() function is used
to convert a string to an integer. Its syntax is:
Lang.parseInt(string);
If
string cannot be converted to the integer type or if there are
any errors, parseInt() returns
an invalid value.
The
following WMLScript examples demonstrate the behavior of the
parseInt() function:
x
= Lang.parseInt("100"); y =
Lang.parseInt(" 100 "); z = Lang.parseInt("+100");
After
executing the above script, the variables x
to z have the integral
value 100.
z
= Lang.parseInt("-100");
After
executing the above script, z
has the integral value -100.
x
= Lang.parseInt("WMLScript Tutorial"); y =
Lang.parseInt(true);
After
executing the above script, both x
and y have the invalid
value.
x
= Lang.parseInt("100abc"); y =
Lang.parseInt("100.999"); z = Lang.parseInt(100.8);
After
executing the above script, the variables x
to z have the integral value
100.
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