Help with array in KSH

maddyfreaks · 08-13-2018, 10:38 AM

Hi Team - Below is my file

VA1|20|20|40
VA2|30|45|50
VA3|45|50|50

expected output

VA1=20,VA2=30,VA3=50

wanted to acheive this with array in KSH as i am writing script in KSH

This is what I did

while IFS="|" read -r A B C D
do
echo "$A=$C,"
done

but getting output like this
VA1=20,
VA2=30,
VA3=50,

If I use paste command last variable will have "," at the end - so want to have array used
can you please guide/assit

scasey · 08-13-2018, 10:51 AM

Code:

echo -n

will suppress the default newline.

Ideas for knowing when to print the comma:

Determine how many lines there are in your input, then increment a counter and only print the comma when it's not the last line.
Print the first line with no comma, then precede each subsequent line with a comma.

Not sure how using an array will help, except that's one way to manage idea #1. Another is to just

Code:

nbr_lines = $(wc -l <inputfile>)

to populate a variable with the number of lines to be processed.

maddyfreaks · 08-13-2018, 11:59 AM

Thanks for the help
Since am new bee - can you give me some sample code I will try to enhance

or if we can write with array that will be a great help.

scasey · 08-13-2018, 12:13 PM

Code:

while IFS="|" read -r A B C D
cnt=0
do
cnt++
if $cnt>1
  echo -e ","
fi
  echo -e "$A=$C"
done

Untested. Play with it.

lougavulin · 08-13-2018, 04:43 PM

According to the title, I thought you talked about things like :

Code:

foo[2]=bar

To do what you want I will go with Awk, but Ksh can do the job !

maddyfreaks · 08-14-2018, 09:39 AM

all I want is pull the contents from the file and make them into 1 variable
Though this is easily achievable from ARRAY

So is req. some assistance from experts

MadeInGermany · 08-14-2018, 03:26 PM

You can post-format with paste as follows

Code:

while IFS="|" read -r A B C D
do
  echo "$A=$C"
done < file | paste -sd, -

With shell builtins

Code:

sep=""
while IFS="|" read -r A B C D
do
  printf "${sep}%s" "$A=$C"
  sep=","
done < file
echo ""

MadeInGermany · 08-14-2018, 04:22 PM

Arrays are often not useful in shell.
The following makes some use of an indexed array:

Code:

i=0
while IFS="|" read -r A B C D
do
  ARR[i++]=$C
done
echo "${ARR[@]}"

ondoho · 08-14-2018, 11:51 PM

Quote:

Originally Posted by MadeInGermany

With shell builtins

Code:

sep=""
while IFS="|" read -r A B C D
do
  printf "${sep}%s" "$A=$C"
  sep=","
done < file
echo ""

nice trick with the commas!

scasey · 08-15-2018, 12:56 AM

Quote:

Originally Posted by MadeInGermany

Code:

sep=""
while IFS="|" read -r A B C D
do
  printf "${sep}%s" "$A=$C"
  sep=","
done < file
echo ""

Slick!
"Counter? We don't need no stinkin' counter!"

MadeInGermany · 08-15-2018, 04:22 AM

The following artwork can deepen your shell knowledge

Code:

myread(){
  IFS="|" read -r A B C D
}
if myread
then
  while
    out="$A=$C"
    myread
  do
    printf "%s," "$out"
  done
  echo "$out"
fi < file

Notes:

if-then-fi is a code block that can be redirected
There can be more than one statement between while-do