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comparing numbers in a file

 
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# 1  
Old 09-20-2007
comparing numbers in a file
Hello, I'm searching for a quick method to read numeric values from a file or a defined variable and identifying the largest number. For instance if the following numbers are in a file or defined to a variable:
09192007 09202007 09182007 09172007 09162007

What "short" method could be used to id "09202007" as being the largest number read in?

Thanks much!
# 2  
Old 09-20-2007
I would use 'bc' to do comparisons.
# 3  
Old 09-21-2007
Hi.

Command sort is very good at comparisons. It may take some manipulation ingenuity to get the numeric strings in an appropriate form, but once obtained, such a method would be very scalable ... cheers, drl
# 4  
Old 09-21-2007
Assuming that the numbers are in a variable, something like this will work:

Code:
a="09192007 09202007 09182007 09172007 09162007"
echo $a | tr ' ' '\n' | sort
09162007
09172007
09182007
09192007
09202007

You can tr the '\n' back to ' ' later if you want.

If the numbers are in a file, you can use a similar method:
Code:
tr ' ' '\n' < /file/with/numbers | sort 
09162007
09172007
09182007
09192007
09202007

# 5  
Old 09-21-2007
just for that one line of numbers in that file

output:
Code:
# awk '{for ( i=1;i<=NF;i++) if ( temp < $i ){temp=$i }}END { print temp }' "file"
09202007

# 6  
Old 09-21-2007
This is cheating a little bit. Smilie Very quick, though.
Code:
$ cat largest
#! /usr/bin/ksh
a="09192007 09202007 09182007 09172007 09162007"
eval set -s -A  n  $a
echo ${n[${#n[*]}-1]}
$ ./largest
09202007
$

# 7  
Old 09-21-2007
With the Z-Shell:

Code:
zsh 4.3.4% v=(09192007 09202007 09182007 09172007 09162007)
zsh 4.3.4% print ${${(On)v}[1]}                         
09202007

Or, in this case, just:
Code:
zsh 4.3.4% print  ${${(O)v}[1]} 
09202007

 
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