如何在数组中查找整数的长度

Question

I want to be able to find the length of a certain value within an array. I have tried:

String.valueOf(array[arrayValue])

but I am unable to see if it is < a certain number within an if statement. For example I want to see if the length of the certain value at hand is less than four. I have something like this right now:

if(String.valueOf(array[arrayValue] < 4)){
    //does something
}

However it says that I cannot use the "<" sign for some reason. Does anyone know how I would successfully be able to do this?

Answer 1

What you want is

if(Integer.toString(array[arrayValue]).length()>4)

This takes the arrayValue th element from your array, converts it to a String , finds the length, then compares that to 4 .

Your current code is taking the arrayValue th element from your array, comparing it to 4 , and then converting the result of the comparison true or false to a String: "true" or "false" . It is then trying to pass the String to the if clause, which only takes boolean, so its throwing an error.

Answer 2

The cause of the code not being compiled is already pointed out by k_g .
However, your statement

it says that I cannot use the "<" sign for some reason

is not entirely true: String.valueOf(array[arrayValue] < 4) is perfectly valid, but it returns a String, and that's not possible as condition in an if-statement.

Getting the 'length' of an integer

To calculate the length – I prefer to say 'width' – of an integer, there are two approaches:

• One might want to convert the integer to a string and getting the length of the string, see k_g 's answer, but conversion to string is expensive .

• A better approach might be this:
  Repeatedly divide the given value by 10 until it drops below 1:

   public static int getWidth(int value) { int i = 0; while (value > 0) { value /= 10; i++; } return i; } 

  It avoids int-to-string conversion, making it approximately 5.6 times faster .