LinuxQuestions.org
Share your knowledge at the LQ Wiki.
Go Back   LinuxQuestions.org > Forums > Linux Forums > Linux - Newbie
User Name
Password
Linux - Newbie This Linux forum is for members that are new to Linux.
Just starting out and have a question? If it is not in the man pages or the how-to's this is the place!

Notices


Reply
  Search this Thread
Old 01-16-2014, 12:42 AM   #1
jags1984
Member
 
Registered: Mar 2013
Posts: 83

Rep: Reputation: Disabled
Dyanmic query in awk


Hi,


How to write Dynamic query in awk.

Say I have a awk query something like :

count=$(awk -F "|" '!/^#/ && !/^$/ {if( $1=="'$Name'" && $NF=="N")print $0}' $FILE |wc -l)

I want to make the condition inside If statement as dyanamic

Ex: var="'$'1=="C_Calendar" && '$'NF=="N"";
count=$(awk -F "|" '!/^#/ && !/^$/ {if($var)print $0}' $FILE |wc -l) --> This doesn't work is it possible in awk ?
 
Old 01-16-2014, 12:47 AM   #2
grail
LQ Guru
 
Registered: Sep 2009
Location: Perth
Distribution: Manjaro
Posts: 9,243

Rep: Reputation: 2684Reputation: 2684Reputation: 2684Reputation: 2684Reputation: 2684Reputation: 2684Reputation: 2684Reputation: 2684Reputation: 2684Reputation: 2684Reputation: 2684
Could you explain a little further as I am not following?

You can utilise bash variables using -v
 
Old 01-16-2014, 01:04 AM   #3
jags1984
Member
 
Registered: Mar 2013
Posts: 83

Original Poster
Rep: Reputation: Disabled
I want to build a dynamic query using awk,

like today if we have 2 conditions tested here
tomorrow I can just modify the string and Add a third condition to test.


The following query with -v option didnt work



var="$1=="DANNY" && $NF=="N"";
echo $var;
count=echo $(awk -v $var=var -F "|" '!/^#/ && !/^$/ {if($var)print $0}' $FILE |wc -l);
echo $count;


Error Thrown
==DANNY && ==N
awk: fatal: `' is not a legal variable name
bash: 0: command not found...
 
Old 01-16-2014, 01:39 AM   #4
grail
LQ Guru
 
Registered: Sep 2009
Location: Perth
Distribution: Manjaro
Posts: 9,243

Rep: Reputation: 2684Reputation: 2684Reputation: 2684Reputation: 2684Reputation: 2684Reputation: 2684Reputation: 2684Reputation: 2684Reputation: 2684Reputation: 2684Reputation: 2684
Firstly, please use [code][/code] tags when showing code or data.

Ok ... I think I get you.

The short answer is no you can't at least not the way you have tried (obviously).
Code:
var="$1=="DANNY" && $NF=="N"";
This will create a string which will still be a string when used in awk, hence your if in the script would be the same as saying:
Code:
if("==DANNY && ==N")
This will always evaluate to true.

If you are wondering why your string is incomplete:

$1 will only have a value if an argument has been passed to the script

$NF is only known to awk unless you create a variable in bash with the same name

Hence both your strings are blank.

The $ symbol in bash is used to return the value assigned to a variable whereas in awk it is used to return the indirect value (ie if NF = 6 then $NF returns the item in the sixth column)
This is why $var has not worked and thrown an error in awk

Your assigment for the awk variable is the wrong way around:
Code:
-v $var=var
Here $var is not a legal name and even if it were, you would be assigning nothing as to call the value of a bash variable you need to use $.
So correct line would be:
Code:
-v var="$var"
This will get us to the situation I explained earlier though for when we now do:
Code:
if(var)
This will test that the variable has a value which is true (always unless $var from bash is empty)

The only way I can think of off the top of my head would be to assign all the values for the tests into a single string and then split into an array and test.
If you then wanted to perform other tests, ie not just equals to, this would be come very complicated as you would need to test for the test and perform each as found??

So this method would be:
Code:
var="1 DANNY NF N"

awk -v var="$var" 'BEGIN{n = split(var, arr);}{<perform tests on each part of array arr testing 1 against 2, 3 against 4 ...>}'
Not sure if that helps. generally I would say you need to rethink your process and what your goal is as perhaps this is not the best method
 
Old 01-16-2014, 06:49 AM   #5
jags1984
Member
 
Registered: Mar 2013
Posts: 83

Original Poster
Rep: Reputation: Disabled
Not only column value, the column number is also dynamic in this case.
 
Old 01-16-2014, 07:52 AM   #6
AwesomeMachine
Senior Member
 
Registered: Jan 2005
Location: USA and Italy
Distribution: Debian testing/sid; OpenSuSE; Fedora
Posts: 1,828

Rep: Reputation: 256Reputation: 256Reputation: 256
I tend to agree with grail. PERL, while still a scripting language, has a bit more flexibility that you'd be looking for. OR, you could do the selection in a shell script and call an awk script to do the parsing.
 
Old 01-16-2014, 02:56 PM   #7
danielbmartin
Senior Member
 
Registered: Apr 2010
Location: Apex, NC, USA
Distribution: Mint 17.3
Posts: 1,482

Rep: Reputation: 411Reputation: 411Reputation: 411Reputation: 411Reputation: 411
With this InFile1 ...
Code:
four score and seven years ago our fathers brought forth
on this continent a new nation conceived in liberty
and dedicated to the proposition that all men are created equal
now we are engaged in a great civil war testing whether that nation
or any nation so conceived and so dedicated can long endure
... and this InFile2 ...
Code:
6 nation
3 chevrolet
4 engaged
1 four
... this awk ...
Code:
awk '{if (FNR==NR){numb[NR]=$1;text[NR]=$2}
      else {for (j in numb)
        if(text[j]==$numb[j]) print}}' $InFile2 $InFile1 >$OutFile
... produced this OutFile ...
Code:
four score and seven years ago our fathers brought forth
on this continent a new nation conceived in liberty
now we are engaged in a great civil war testing whether that nation
Daniel B. Martin

Last edited by danielbmartin; 01-16-2014 at 03:00 PM.
 
Old 01-16-2014, 09:28 PM   #8
danielbmartin
Senior Member
 
Registered: Apr 2010
Location: Apex, NC, USA
Distribution: Mint 17.3
Posts: 1,482

Rep: Reputation: 411Reputation: 411Reputation: 411Reputation: 411Reputation: 411
Here is a minor variation of the solution posted earlier.
This makes the matched word STAND OUT.

With this InFile1 ...
Code:
four score and seven years ago our fathers brought forth
on this continent a new nation conceived in liberty
and dedicated to the proposition that all men are created equal
now we are engaged in a great civil war testing whether that nation
or any nation so conceived and so dedicated can long endure
... and this InFile2 ...
Code:
6 nation
3 chevrolet
4 engaged
1 four
... this awk ...
Code:
awk '{if (FNR==NR){numb[NR]=$1;text[NR]=$2}
      else {for (j in numb)
        if(text[j]==$numb[j])
          {$numb[j]=toupper($numb[j]);print}}}'  \
   $InFile2 $InFile1 >$OutFile
... produced this OutFile ...
Code:
FOUR score and seven years ago our fathers brought forth
on this continent a new NATION conceived in liberty
now we are ENGAGED in a great civil war testing whether that nation
Daniel B. Martin

Last edited by danielbmartin; 01-17-2014 at 07:28 AM. Reason: Cosmetic improvement; no code change.
 
Old 01-17-2014, 12:06 AM   #9
jags1984
Member
 
Registered: Mar 2013
Posts: 83

Original Poster
Rep: Reputation: Disabled
Hi Daniel,

This doesnt looks a solution for the query, it looks like dynamic qury in awk seems a little difficult.

Last edited by jags1984; 01-17-2014 at 12:08 AM.
 
Old 01-17-2014, 02:29 AM   #10
grail
LQ Guru
 
Registered: Sep 2009
Location: Perth
Distribution: Manjaro
Posts: 9,243

Rep: Reputation: 2684Reputation: 2684Reputation: 2684Reputation: 2684Reputation: 2684Reputation: 2684Reputation: 2684Reputation: 2684Reputation: 2684Reputation: 2684Reputation: 2684
Daniels solution is dynamic as it means you simply add to the second file (InFile2) as many entries as you wish and those will be the rows and words searched for in the main file
 
Old 01-17-2014, 04:32 AM   #11
jags1984
Member
 
Registered: Mar 2013
Posts: 83

Original Poster
Rep: Reputation: Disabled
Ok I got it. This is for Single column field,
if I need to check multiple column field (each column check having an AND condition)


At any time if I want to check different columns...

My query can be any of these

Code:
count=$(awk -F "|" '!/^#/ && !/^$/ {if( $1=="'$Name'" && $NF=="N")print $0}' $FILE |wc -l)
Code:
count=$(awk -F "|" '!/^#/ && !/^$/ {if( $1=="'$Name'" && $4=="'Place'" $NF=="N")print $0}' $FILE |wc -l)
Code:
count=$(awk -F "|" '!/^#/ && !/^$/ {if( $1=="'$Name'" && $4=="'Place'" && $5=="'$Date'" && $NF=="N")print $0}' $FILE |wc -l)
 
Old 01-17-2014, 11:15 AM   #12
grail
LQ Guru
 
Registered: Sep 2009
Location: Perth
Distribution: Manjaro
Posts: 9,243

Rep: Reputation: 2684Reputation: 2684Reputation: 2684Reputation: 2684Reputation: 2684Reputation: 2684Reputation: 2684Reputation: 2684Reputation: 2684Reputation: 2684Reputation: 2684
So loop over all fields and only when all true, proceed
 
Old 01-17-2014, 03:51 PM   #13
tabbygirl1990
Member
 
Registered: Jul 2013
Location: a warm beach, cool ocean breeze, nice waves, and a Margaritta
Distribution: RHEL 5.5 Tikanga
Posts: 63

Rep: Reputation: 1
WOW!

you guys are a thing of beauty to watch
 
Old 01-19-2014, 04:42 PM   #14
danielbmartin
Senior Member
 
Registered: Apr 2010
Location: Apex, NC, USA
Distribution: Mint 17.3
Posts: 1,482

Rep: Reputation: 411Reputation: 411Reputation: 411Reputation: 411Reputation: 411
InFile1 ...
Code:
four score and seven years ago our fathers brought forth
on this continent a new nation conceived in liberty
and dedicated to the proposition that all men are created equal
now we are engaged in a great civil war testing whether that nation
or any nation so conceived and so dedicated can long endure
InFile2 ...
Code:
6 nation 3 continent
4 engaged 7 civil
1 four
Search InFile1 for all lines which satisfy any of the criteria specified in InFile2.
They are:
Code:
- all lines where the 6th word is nation and the 3rd word is continent
- all lines where the 4th word is engaged and the 7th word is civil
- all lines where the 1st word is four
This awk ...
Code:
awk '{if (FNR==NR) for (i=1;i<=NF;i++) crit[NR,i]=$i
      else for (j=1;j<=NR;j++) {hits=0; misses=0; k=-1;
         while (crit[j,k=k+2]!="") 
           if (crit[j,k+1]!=$crit[j,k]) {misses++; break}
           else {$crit[j,k]=toupper($crit[j,k]); hits++}
      if (hits>0&&misses==0) print}}' $InFile2 $InFile1 >$OutFile
... produced this OutFile ...
Code:
FOUR score and seven years ago our fathers brought forth
on this CONTINENT a new NATION conceived in liberty
Daniel B. Martin

Last edited by danielbmartin; 01-19-2014 at 08:19 PM. Reason: Tighten the code, slightly
 
Old 01-20-2014, 03:44 AM   #15
grail
LQ Guru
 
Registered: Sep 2009
Location: Perth
Distribution: Manjaro
Posts: 9,243

Rep: Reputation: 2684Reputation: 2684Reputation: 2684Reputation: 2684Reputation: 2684Reputation: 2684Reputation: 2684Reputation: 2684Reputation: 2684Reputation: 2684Reputation: 2684
Nice work Daniel. Here is another take using your data:
Code:
awk 'NR==FNR{for(i=1;i<NF;i+=2)arr[NR][$i]=$(i+1)}
          {for(j=1;j <= length(arr);j++){
             for(k in arr[j])
               if( $k == arr[j][k] )a++;
             if(a == length(arr[j]))print;
             a=0
          }}' f2 f1
 
  


Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is Off
HTML code is Off



Similar Threads
Thread Thread Starter Forum Replies Last Post
awk query jkeertir Linux - Newbie 3 01-17-2014 05:12 AM
[SOLVED] Awk Query gregmcc Linux - Newbie 10 08-21-2013 09:55 AM
[SOLVED] Awk query shivaa Linux - Newbie 4 12-01-2012 06:53 AM
awk query jkeertir Linux - Networking 3 04-07-2008 09:07 AM
awk program. a little query! indiancosmonaut Programming 7 07-05-2007 10:48 AM


All times are GMT -5. The time now is 06:37 PM.

Main Menu
Advertisement
My LQ
Write for LQ
LinuxQuestions.org is looking for people interested in writing Editorials, Articles, Reviews, and more. If you'd like to contribute content, let us know.
Main Menu
Syndicate
RSS1  Latest Threads
RSS1  LQ News
Twitter: @linuxquestions
Facebook: linuxquestions Google+: linuxquestions
Open Source Consulting | Domain Registration