How can I check if a value is of type Integer?
If input value can be in numeric form other than integer , check by
if (x == (int)x)
{
// Number is integer
}
If string value is being passed , use Integer.parseInt(string_var).
Please ensure error handling using try catch in case conversion fails.
If you have a double/float/floating point number and want to see if it's an integer.
public boolean isDoubleInt(double d)
{
//select a "tolerance range" for being an integer
double TOLERANCE = 1E-5;
//do not use (int)d, due to weird floating point conversions!
return Math.abs(Math.floor(d) - d) < TOLERANCE;
}
If you have a string and want to see if it's an integer. Preferably, don't throw out the Integer.valueOf()
result:
public boolean isStringInt(String s)
{
try
{
Integer.parseInt(s);
return true;
} catch (NumberFormatException ex)
{
return false;
}
}
If you want to see if something is an Integer object (and hence wraps an int
):
public boolean isObjectInteger(Object o)
{
return o instanceof Integer;
}
if (x % 1 == 0)
// x is an integer
Here x
is a numeric primitive: short
, int
, long
, float
or double
Try maybe this way
try{
double d= Double.valueOf(someString);
if (d==(int)d){
System.out.println("integer"+(int)d);
}else{
System.out.println("double"+d);
}
}catch(Exception e){
System.out.println("not number");
}
But all numbers outside Integers range (like "-1231231231231231238") will be treated as doubles. If you want to get rid of that problem you can try it this way
try {
double d = Double.valueOf(someString);
if (someString.matches("\\-?\\d+")){//optional minus and at least one digit
System.out.println("integer" + d);
} else {
System.out.println("double" + d);
}
} catch (Exception e) {
System.out.println("not number");
}
You should use the instanceof
operator to determine if your value is Integer or not;
Object object = your_value;
if(object instanceof Integer) {
Integer integer = (Integer) object ;
} else {
//your value isn't integer
}