View Full Version : Getting first digits in a number

jomak73

07-19-2010, 07:59 PM

Ooook so this is probably the stupidest question ever. I know in java you can take advantage of a number being an int (not double) and divide by something without getting a remainder. But in javascript you dont declare what kind of variable something is.

So my problem is: Given any double or triple digit number, how do i get all but the last digit. Like if i have 13, I need to make an int with 1. If it's 103 i need one with 10.

Thanks!!

RandomUser531

07-19-2010, 08:43 PM

If the number has only one digit:

The first function returns 0.

The second function returns the number unchanged.

function getDigits( num )

{

var str = Math.round( num ).toString();

return Number( str.substring( 0, str.length - 1 ) );

}

function getDigits( num )

{

var n = Math.round( num ).toString().match( /(\d+)(\d)/ );

return Number( n ? n[ 1 ] : num );

}

mrhoo

07-19-2010, 08:58 PM

Given any double or triple digit number (N)

N=Math.floor(N/10)

Old Pedant

07-19-2010, 09:30 PM

Actually, MrHoo's answer works for any number. Just that if the number is less than 10, you will always get 0 as a result. (And of course negative numbers come out strangely:

Math.floor( -173.20 / 10 ) ) ==>> -18

but we'll presumably ignore that?)

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