1

So I have a big file containing the values of a matrix with the folowing format:

(0,0) 0.6666
(0,1) 0.0000
(0,2) 1.3333
...

And I want to convert it to:

0 0 0.6666e+00
0 1 0.0000e+00
0 2 1.3333e+00
...

I can do this with the following script:

#!/bin/bash

input="$1"
while read coord val; do
   printf "%s" "${coord//,/ }" | awk -F '[()]' '{printf "%s",$(NF-1)}'  
   printf " %8.3e\n" "$val"
done < "$input"

But this is extremely slow for my case ( 9409 lines) How can I do this faster?

2

Here's a slightly different awk approach. This should be faster than using sub and gsub1:

awk -F'[(,)]' '{printf "%s %s %8.3e\n",$2,$3,$4}' file

1I tested it on a file with 5000000 lines and it was ~2seconds faster than the gsub/sub approach. Not a great difference but it might be important for huge files.

  • Yes thats faster, and it gives more control. Maybe I need to transform it to 0-base arrays to 1-base array and I can do it with ++$2, ++$3. Thanks! – Msegade Feb 26 '16 at 13:30
2

It will be faster if you let awk do it alone:

awk '
{
  gsub("[()]", "", $1)
  sub(",", " ", $1)
  $2 = sprintf("%8.3e", $2)
  print
}' <file

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