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Using NR in AWK

 
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# 1  
Old 08-24-2011
MySQL Using NR in AWK
Hi ,i need to loop through records and print only specific column.
How do i that using NR

I have tried the following code
If i give NR==1 or NR==2,i am able to print the specific column,but if use NR==$i and loop it ,i am not able to print

Code:
while [ $i -le $Norec ]
                do
                echo  -e "` awk 'NR==$i { print $2}' stat.txt` "   
                echo  -e "` awk 'NR==$i { print $4}' stat.txt`" 
done

please suggest if there other alternatives to print specific column for each record

Thanks in advance

Moderator's Comments:
Mod Comment Please start using [CODE] tags, and create new threads for new posts instead of hijacking other threads
Last edited by pludi; 08-24-2011 at 06:52 AM..
# 2  
Old 08-24-2011
Code:
 
awk -v colno=$i ' if(NR==colno){print $2}' stat.txt

# 3  
Old 08-24-2011
Utilities like awk are efficient when run on batches of data, but take time to load and start, so running multiple instances of awk per loop to process individual lines is extremely inefficient. Imagine only being able to say one word per phone call.

What are you actually trying to do? There may be simpler a way that's hundreds of times faster.
# 4  
Old 08-24-2011
itkamaraj,

i have used your code ,but i am not able to get the desired output.

My requirement is that i need to go through multiple records in a text file and print specific column.

corono688,
Please suggest any alternatives

Thanks in advance
# 5  
Old 08-24-2011
before asking suggestion, why cant you put the example input and required output file and the logic which u tried ?
# 6  
Old 08-24-2011
Quote:
Originally Posted by krashraj
corono688,
Please suggest any alternatives

Thanks in advance
Fixing your code will mean rewriting more than just your awk statements. I need to see your code, or at least a complete explanation of what your script's trying to do.
# 7  
Old 08-25-2011
The details of input file
Code:
student1 male 1year ECE
student2 female 1year EEE
STUDENT3 MALE 2YEAR CSE

nostud will contain the no of records in inpur file.
I need to select each student .For that i have used the first while loop.

In the second while loop i need to print some extra columns along with the ones in input file.
The second loop will be running for no of records required which is an user input.

Code:
j=1
while [ $j -le $nostud ]
        do
                i=1
                while [ $i -le $Norec ]
                do
                echo  -e "` awk 'NR==$j { print $2}' subaccount.txt` \c"        
               #some other code to generate some columns
               i=i+1
done
j=j+1
done

My question is that how do i print details available in input file to the output file
for each record generated for as tudent some columns must be picked up from the input file.
Hope thuis clear.
Thanks in advance

Moderator's Comments:
Mod Comment Please use [code] and [/code] tags when posting code, data or logs etc. to preserve formatting and enhance readability, thanks. Continuing to ignore this will gather you infractions points, that will lead to a permanent ban when reaching an amount of them.
Last edited by zaxxon; 08-25-2011 at 03:15 AM.. Reason: code tags
 
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