String.Length vs. (int) string > val ?

Unity Engine
, ,
1

I have int values that i want to display in TextMeshPro elements.

I turned off AutoSize on all TMP elements to save performance, so i’ve to pre-calculate the fontSize values depending on the number of characters displayed.

Whenever a value changes in any TMP, i check the character count and i just assign the pre-calculated value as fontSize for that count.

To get the number of characters i’m using this:

private void SetFontSize(string str)
{
        var length = str.Length;
        if(length == 1)
        {
           a.fontSize = oneCharFontSize;
        }
        else if(length == 2)
        {
            a.fontSize = twoCharFontSize;
        }
        else if(intStr == 3)
        {
            a.fontSize = threeCharFontSize;
        }
       else if(intStr == 4)
        {
            a.fontSize = fourCharFontSize;
        }
        .....
}

Is it better this way or should i use:

private void SetFontSize(string str)
{
        int intStr = (int) str;
        a.fontSize = oneCharFontSize;
        if(intStr > 9)
        {
           a.fontSize = twoCharFontSize;
        }
        else if(intStr > 99)
        {
            a.fontSize = threeCharFontSize;
        }
        else if(intStr > 999)
        {
            a.fontSize = fourCharFontSize;
        }
        .....
}

Which one is less expensive if i’m doing this A LOT ?

2

Why not put all of your precalculated font sizes in an array, and then just do this:

int[] fontSizes;

private void SetFontSize(string str)
{
    var length = str.Length;
    a.fontSize = fontSizes[length - 1];
}
3

@PraetorBlue
That’s what i’m doing actually i don’t know why i wrote the if else statements, but my question is about the .Length function:
is it expensive to use? should i just cast to int and check if larger than 9 and 99 and 999 respectively?

Keep in mind that i’m doing this like 40 times per second.

4

Length is not expensive to use. Parsing the string to an int is definitely slower. I don’t think it’s like strlen in C where it traverses the whole string to find a null terminator. Even if it was, parsing would require reading the whole string too and doing a lot more work than just counting the characters.

2 Likes
5

Well if this is the case then i’ll stay with .Length

Thank you man :slight_smile: