comparing numbers in a file

dusk2dawn · #1 (**permalink**) 09-20-2007

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!

porter · #2 (**permalink**) 09-20-2007

I would use 'bc' to do comparisons.

drl · #3 (**permalink**) 09-20-2007

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

blowtorch · #4 (**permalink**) 09-20-2007

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

ghostdog74 · #5 (**permalink**) 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

Perderabo · #6 (**permalink**) 09-21-2007

This is cheating a little bit.

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
$

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