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[BASH] Regex for floating point number

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# 1  
Old 12-28-2011
[BASH] Regex for floating point number
Hey again,

I have a basic regex that tests if a number is a float.


Thank you.
Last edited by whyte_rhyno; 12-30-2011 at 05:16 PM..
# 2  
Old 12-28-2011
Code:
sed -n '/^-*[0-9]*[.]*[0-9]*$/p' myFile

Last edited by vgersh99; 12-28-2011 at 03:15 PM..
# 3  
Old 12-28-2011
Quote:
Originally Posted by vgersh99
Code:
sed -n '/^[-]*[0-9]*[.]*[0-9]*$/p' myFile

Thanks for the reply.

Sadly that regex allows for multiple minus signs and multiple decimal points.

For example:

------------------9......................3

Is valid with that regex.

Thanks anyway, though.
# 4  
Old 12-28-2011
It doesn't take much of a change:
Code:
$ sed -En '/^-?[0-9]*[.]?[0-9]+$/p' file
-10.4
1.0

(if your sed doesn't support extended regular expressions, grep surely will grep -E '^-?[0-9]*[.]?[0-9]+$' file)
# 5  
Old 12-28-2011

I prefer to use the shell rather than an external command.

This is a beginning (I'm not at my computer right now so I don't have the full function):
Code:
is_fpnum()
{
  case $1 in
    *[!-0-9]* | *.*.* | -*-* ) ## add invalid patterns as needed
             return 1;;
  esac
}

# 6  
Old 12-28-2011
Disregard the last post I made, I had a stupid error in it. All working now.

Thank you, all.
Last edited by whyte_rhyno; 12-30-2011 at 10:22 AM..
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