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Copy last few lines of a file, perform math operation and iterate further

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# 1  
Old 02-23-2019
Copy last few lines of a file, perform math operation and iterate further
Hi,


I am trying to generate a data of following order:
Code:
4 0 1 642 643
4 642 643 1283 1284
4 1283 1284 1924 1925
4 1924 1925 2565 2566
4 2565 2566 3206 3207
4 3206 3207 3847 3848
4 3847 3848 4488 4489
4 4488 4489 5129 5130
 ----------------------

4 1 2 643 644
4 643 644 1284 1285
4 1284 1285 1925 1926
4 1925 1926 2566 2567
4 2566 2567 3207 3208
4 3207 3208 3848 3849
4 3848 3849 4489 4490
4 4489 4490 5130 5131 
--------------------- 
4 2 3 644 645
4 644 645 1285 1286
4 1285 1286 1926 1927
4 1926 1927 2567 2568
4 2567 2568 3208 3209
4 3208 3209 3849 3850
4 3849 3850 4490 4491
4 4490 4491 5131 5132

where the 1st column is a constant with value 4. Values in columns 2,3,4,5 are incremented by 1 based on the data of previously available 8 rows.

I have tried:
Code:
BEGIN {FS=" "}
{
 i = 1
 while (i<=2)
 {
  printf ("%f ", tail-8)
  i++
 }
printf ("\n");
}

But the output is -8.000. I am trying to use the previous 8 lines for an increment operation but it sees this as a number to output.
Any suggestions?
# 2  
Old 02-23-2019
see if it helps.
If sapa.txt is:
Code:
4 0 1 642 643
4 642 643 1283 1284
4 1283 1284 1924 1925
4 1924 1925 2565 2566
4 2565 2566 3206 3207
4 3206 3207 3847 3848
4 3847 3848 4488 4489
4 4488 4489 5129 5130

running awk -v rep=3 -f sapa.awk sapa.txt
where
sapa.awk is:
Code:
BEGIN {
  if (!rep) rep=5
}
{
   for(i=1;i<=NF;i++)
      a[FNR%8,i]=$i
   nf=NF
}
1
END {
   print "---"
   for(cnt=1;cnt<=rep;cnt++)  {
     for(row=1;row<=8;row++) {
       printf("%s%s", $1, OFS)
       for(i=2;i<=nf;i++)
         printf("%s%s", ++a[row%8,i], (i==nf)?ORS:OFS)
     }
     print "---"
   }
}

produces:
Code:
4 0 1 642 643
4 642 643 1283 1284
4 1283 1284 1924 1925
4 1924 1925 2565 2566
4 2565 2566 3206 3207
4 3206 3207 3847 3848
4 3847 3848 4488 4489
4 4488 4489 5129 5130
---
4 1 2 643 644
4 643 644 1284 1285
4 1284 1285 1925 1926
4 1925 1926 2566 2567
4 2566 2567 3207 3208
4 3207 3208 3848 3849
4 3848 3849 4489 4490
4 4489 4490 5130 5131
---
4 2 3 644 645
4 644 645 1285 1286
4 1285 1286 1926 1927
4 1926 1927 2567 2568
4 2567 2568 3208 3209
4 3208 3209 3849 3850
4 3849 3850 4490 4491
4 4490 4491 5131 5132
---
4 3 4 645 646
4 645 646 1286 1287
4 1286 1287 1927 1928
4 1927 1928 2568 2569
4 2568 2569 3209 3210
4 3209 3210 3850 3851
4 3850 3851 4491 4492
4 4491 4492 5132 5133
---

These 3 Users Gave Thanks to vgersh99 For This Post:
Neo RudiC SaPa
# 3  
Old 02-23-2019
Try also


Code:
awk '
T[NR]=$0

END     {for (k=1; k<=REP; k++) {++INC
                                 print "----"
                                 for (j=1; j<=NR; j++)  {$0 = T[j]
                                                         for (i=2; i<=NF; i++) $i+=INC
                                                         print
                                                        }
                                }
        }
' REP=3 file
4 0 1 642 643
4 642 643 1283 1284
4 1283 1284 1924 1925
4 1924 1925 2565 2566
4 2565 2566 3206 3207
4 3206 3207 3847 3848
4 3847 3848 4488 4489
4 4488 4489 5129 5130
----
4 1 2 643 644
4 643 644 1284 1285
4 1284 1285 1925 1926
4 1925 1926 2566 2567
4 2566 2567 3207 3208
4 3207 3208 3848 3849
4 3848 3849 4489 4490
4 4489 4490 5130 5131
----
4 2 3 644 645
4 644 645 1285 1286
4 1285 1286 1926 1927
4 1926 1927 2567 2568
4 2567 2568 3208 3209
4 3208 3209 3849 3850
4 3849 3850 4490 4491
4 4490 4491 5131 5132
----
4 3 4 645 646
4 645 646 1286 1287
4 1286 1287 1927 1928
4 1927 1928 2568 2569
4 2568 2569 3209 3210
4 3209 3210 3850 3851
4 3850 3851 4491 4492
4 4491 4492 5132 5133

These 3 Users Gave Thanks to RudiC For This Post:
nezabudka SaPa vgersh99
# 4  
Old 02-23-2019
Code:
#!/bin/bash
bc <<<'
define row (t,j) { auto n, p, b
        m = 642;
        for ( i=1; i<=8; i++ ) {
        print 4," ",t+n-p+b," ",t+n+1-p+b," ",t+n+m-p," ",t+n+m+1-p++,"\n"
        n+=m; b=1
        }
        print "----------\n"
        if(--j) o = row (++t,j)
}
o = row (0,4)'

These 2 Users Gave Thanks to nezabudka For This Post:
RudiC SaPa
# 5  
Old 02-23-2019
Thanks for the replys!!



I could do the required in the following simple few lines (as many have answer as well!!).

Code:
#!/bin/bash
for k in {1..639}
do
   echo "$k th iteration"
   tail -8 MWE.txt > i
   awk '{print $1, $2+1, $3+1, $4+1, $5+1}' i > j
   cat j >> MWE.txt
done

These 2 Users Gave Thanks to SaPa For This Post:
nezabudka RudiC
# 6  
Old 02-24-2019
Hi SaPa,


thanks for sharing your working (!) approach.
Pls be aware that it contains elements that were not specified in post #1 and thus could not be covered by the proposals given. Also, running 3 external commands in extra processes, plus 4 file operations (open), for each of the 639 iterations might not be the most efficient usage of resources.


@nezabudka: Thanks for your "exotic" approach, giving me and my aspects / perspective / tool box a new dimension!
This User Gave Thanks to RudiC For This Post:
nezabudka
# 7  
Old 02-24-2019
At least you should consider a pipe and no cat, while in this case the input file and output file are identical, so you need one temp file.
Code:
   tail -8 MWE.txt >i
   awk '{print $1, $2+1, $3+1, $4+1, $5+1}' i >> MWE.txt

Last edited by MadeInGermany; 02-24-2019 at 06:52 AM..
This User Gave Thanks to MadeInGermany For This Post:
nezabudka
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