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Calc max of a column

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# 1  
Old 03-30-2010
Calc max of a column
In C that was easy with a for and if. Iam trying to learn a litle more in bash.

Example

Ronaldo:5800
Figo:4000
Rafael:2321
Kaka:1230

I want the max of the $2 and the output will be:

The max value is 5800 from Ronaldo.

How can i do this in shell?
Thanks for all, folks.
Last edited by rafazz; 03-30-2010 at 02:46 PM..
# 2  
Old 03-30-2010
Code:
$
$ cat f2
Ronaldo:5800
Figo:4000
Rafael:2321
Kaka:1230
$
$ cat f2.sh
#!/usr/bin/bash
IFS=:
while read name amt
do
  [[ "$amt" -ge "${MAX}" ]] && MAX=$amt
done <f2
echo "Max value = $MAX"
$
$ ./f2.sh
Max value = 5800
$
$

tyler_durden
# 3  
Old 03-30-2010
I am getting the content from file.sh
Code:
name:price
Ronaldo:5800
Figo:4000
Rafael:2321
Kaka:1230

I write this..
Code:
while read name price
do
  [[ "$price" -ge "${MAX}" ]] && MAX=$price
done <$price
echo "Max value = $MAX" ;

The error..
Code:
./file.sh: line 29: $price: ambiguous redirect

Last edited by Scott; 03-30-2010 at 06:14 PM.. Reason: Please use code tags
# 4  
Old 03-30-2010
Quote:
Originally Posted by rafazz
...
The error..

./file.sh: line 29: $price: ambiguous redirect
You will have to redirect from your data file, not from a value of a variable.

tyler_durden
# 5  
Old 03-30-2010
Code:
$ sort -t":" -knr2 file | IFS=":" read x y
$ echo $y
5800

Code:
awk -F":" ' $2>s{s=$2} END{print s} ' file

# 6  
Old 03-30-2010
Quote:
Originally Posted by rafazz
Iam getting the content from file.sh
nameSmilierice
Ronaldo:5800
Figo:4000
Rafael:2321
Kaka:1230

I write this..

while read name price
do
[[ "$price" -ge "${MAX}" ]] && MAX=$price
done <$price
echo "Max value = $MAX" ;

The error..

./file.sh: line 29: $price: ambiguous redirect
Look at durden_tyler's code more closely. It sets IFS to the value necessary to properly split the lines with read. It looks like you omitted the IFS modification. If so, without any whitespace in the line, the entire line (sans leading whitespace) will be assigned to $name. $price will be empty.

Also, as he mentioned above, you're trying to redirect from the wrong place. $price does not contain the name of the file to read.

Regards,
Alister
Last edited by alister; 03-30-2010 at 05:56 PM..
# 7  
Old 03-30-2010
Code:
awk -F":" ' $2>s{s=$2} END{print s} ' file

[/QUOTE]

In this case, the result is the print of my first line of the text, that is name : price. how can i make the prog to start read in second line?

file.sh
name : price
Ronaldo:5800
Figo:4000
Rafael:2321
Kaka:1230
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