Tek-Tips is the largest IT community on the Internet today!
Members share and learn making Tek-Tips Forums the best source of peer-reviewed technical information on the Internet!
-
Congratulations SkipVought on being selected by the Tek-Tips community for having the most helpful posts in the forums last week. Way to Go!
A little math 1
- Thread starter smileyone
- Start date
-
1
- #2
If you know that your result will always be:<br><br>X.Y<br><br>i.e. one digit before and another after the decimal point...<br><br>use:<br><FONT FACE=monospace>print "%1.1f", $num;</font><br><br>or if you don't know how many digits before the point you want:<br><br><FONT FACE=monospace><br>$num = 3.5675737;<br><br>($before,$after) = split(/\./,$num);<br>$before = length $before;<br><br>printf "%$before.1f" , $num;<br></font><br><br>Hope that helps<br>Loon
- Thread starter
- #3
Ok, but I have to add together the rounded answers. I need to print 3.6 but also need to add 3.6 to something else.<br><br>Is there something to round it and still be able to add them together? <br><br>Will what you gave me be able to do that?
The printf doesn't change the value of the scalar no.. it's still 5.56737 etc..<br><br>I'm sure there'll be a way to do it - unfortunately I have no idea how, I suspect there's a CPAN module for this kind of thing somewhere.<br><br>Failing that, could you do the arithmetic first and then round out for the printing at the end?<br><br>Good luck!<br>Loon
There's a companion to the printf function that you can use to format a value, and assign that value to another scalar: sprintf. Here's a quick example:<br><FONT FACE=monospace><br>$Value = 3.141579; # Whatever ;^)<br><br>$Rounded = sprintf("%1.1f", $Value);<br><br>print "Original: ", $Value, "\n";<br>print "Rounded: ", $Rounded, "\n";<br></font> <p> <br><a href=mailto: > </a><br><a href= > </a><br>--<br>
0 1 - Just my two bits
0 1 - Just my two bits
Errmm - don't printf and sprintf just truncate the values - as opposed to rounding them? <p>Mike<br><a href=mailto:michael.j.lacey@ntlworld.com>michael.j.lacey@ntlworld.com</a><br><a href= Cargill's Corporate Web Site</a><br>
They round, but slightly differently from what you may be used to. (At least in the quick test I just did 
<br><br>For example: 0.01 to 0.50 will display as 0.<br><br>0.51 to 0.99 will display as 1.<br><br>0.123 with a format of %1.1f will display as 0.1, as will 0.126. (This gives you 0.13 which in turn rounds down to 0.1.)<br><br>I was always taught that 0.5 and about should round up, but perl seems to do it as anything over 0.5 will round up... <p> <br><a href=mailto: > </a><br><a href= > </a><br>--<br>
0 1 - Just my two bits
<br><br>For example: 0.01 to 0.50 will display as 0.<br><br>0.51 to 0.99 will display as 1.<br><br>0.123 with a format of %1.1f will display as 0.1, as will 0.126. (This gives you 0.13 which in turn rounds down to 0.1.)<br><br>I was always taught that 0.5 and about should round up, but perl seems to do it as anything over 0.5 will round up... <p> <br><a href=mailto: > </a><br><a href= > </a><br>--<br>0 1 - Just my two bits
Ok - that sounds like reasonable behaviour - I'll bear it in mind, thanks Andy. <p>Mike<br><a href=mailto:michael.j.lacey@ntlworld.com>michael.j.lacey@ntlworld.com</a><br><a href= Cargill's Corporate Web Site</a><br>
- Status
Similar threads
