Finding number of significant digits

Significant digits depends on where the number came from (accuracy of the measurement, etc.).  I don't think you can have a computer function that can determine the accuracy of the input.  You would have to pre-define what the inputs represent.

this seems like a good use for a Regular Expression, which i suck at, or just a string comparison with conditionals...

based on the rules here...

1. All non-zero digits are significant.
2. In a number without a decimal point, only zeros BETWEEN non-zero digits are significant (unless a bar indicates the last significant digit--see below).
3. In a number with a decimal point, all zeros to the right of the first non-zero digit are significant.

from....  http://en.wikipedia.org/wiki/Significant_digit


I think there is a pretty good chance that you can come up with an algorithm for it.

maybe a conditional like this...


basically, you just pass a String into the function... if you try to pass a Number, it will take a number like 100.0 and turn it to 100


does this work for you?


rp / ZA

function checkForSig( theNum:String ):int
{
	var sigNums:int;
	if( theNum.indexOf(".") > -1 ) sigNums = theNum.split(".").join("").length;
	else sigNums = theNum.split("0").join("").length;
 
	return sigNums;
}
 
trace( checkForSig( "100.01" ) );  // give me 5

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actually, the last one had a fault...

try this one...  let me know if you can find a number that is not caught...


rp / ZA

// AS 3.0
 
function checkForSig( theNum:String ):int
{
	var sigNums:int;
	if( theNum.indexOf(".") > -1 )
	{
		sigNums = theNum.split(".").join("").length;
	}
	else if( theNum.indexOf("0") > -1 )
	{
		var arr:Array = theNum.split("");
		var len:int = arr.length;
		sigNums = arr[ len - 1 ] == "0" ? theNum.split("0").join("").length : theNum.length;
	}
	else
	{
		sigNums = theNum.length;
	}
	
	return sigNums;
}
 
trace( checkForSig( "10.50" ) );

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Hi rascalpants, I found that your algorithm did not work for 0.0000010 (which should be 2):

trace( checkForSig( "0.0000010" ) );
//outputs 8

and one more update to fix the occurance of 0.00012 as having 6 instead of the correct value of 2...


hope this works for you...  at least it was a fun challenge...


rp / ZA

// AS 3.0
 
function checkForSig( theNum:String ):int
{
	var sigNums:int;
	if( theNum.indexOf(".") > -1 )
	{
		var decArr:Array = theNum.split(".");
		sigNums = decArr[ 0 ] == "0" ? decArr.join("").split("0").join("").length : decArr.join("").length;
	}
	else if( theNum.indexOf("0") > -1 )
	{
		var arr:Array = theNum.split("");
		var len:int = arr.length;
		sigNums = arr[ len - 1 ] == "0" ? theNum.split("0").join("").length : theNum.length;
	}
	else
	{
		sigNums = theNum.length;
	}
	
	return sigNums;
}
 
trace( checkForSig( "120.00" ) );

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you where too quick for me  ;)


rp / ZA

hold on one more second...

:)

rp / ZA

Thanks!

no problem...  I love a challenge  ;)

what exactly can this be used for now?  lol




rp / ZA

I have a graphing component in flash, and in the interest of making a graph that looks nice, I am trying to find a suitable value for the difference between consecutive x-axis labels.  The graphing utility can graph any range of values, and supports zooming and moving around.  This causes some pretty messy numbers to be displayed on the x-axis labels.  This code will help me find the best difference between the consecutive x-labels so the display is intervals are easy to read.

:)

wow...  my code sounds like childs play compared to what you are putting it into

;)

good luck...

rp / ZA