How can I check if a value is of type Integer?

Question

I need to check if a value is an integer. I found this: How to check whether input value is integer or float?, but if I'm not mistaken, the variable there is still of type double even though the value itself is indeed an integer.

Answer 1

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.

Answer 2

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; }