Passing values from file into array in Bash


 
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# 1  
Passing values from file into array in Bash

Hi,

I'm trying to write a bash script that takes a file and passes each line from the file into an array with elements separated by column.

For example:

Sample file "file1.txt":

Code:
1 name1 a first
2 name2 b second
3 name3 c third

and have arrays such as:

Code:
line1 = ( "1" "name1" "a" "first" )
line2 = ( "2" "name2" "b" "second" ) 
line1 = ( "3" "name3" "c" "third" )

I'd also like to know if it's possible to pass each column of values into its own array, such as:

Code:
column1 = ( "1" "2" "3" )
column2 = ( "name1" "name2" "name3" )
column3 = ( "a" "b" "c" )
column4 = ( "first" "second" "third" )

Thank you!

Last edited by Scrutinizer; 11-17-2012 at 12:01 AM.. Reason: code tags
# 2  
Check out the below example, You should be able to modify it to do what you want to accomplish:
Code:
$ cat t
1 name1 a first
2 name2 b second
3 name3 c third


$ cat test.sh
# Script will load file lines into array(datafile) and then fields from each line into array(fields)
# and print each array(fields) element separating each element with the pipe symbol(|).
OLD_IFS=$IFS
IFS=$'\n'
datafile=( `cat "t"`)
IFS=$OLD_IFS
for l in "${datafile[@]}"
do
  fields=( $l );
  for f in $(seq 0 $((${#fields[@]} - 1)))
  do
    echo -n "${fields[$f]}"
    if (( f < $((${#fields[@]} - 1)) )); then
       echo -n "|"
    else
       echo ""
    fi
  done
done


$ test.sh
1|name1|a|first
2|name2|b|second
3|name3|c|third

# 3  
Try this; it works in my linux/bash system:
Code:
$ while read a; do eval row$((i++))="($a)"; done <file
$ for j in row{0..2}; do for ((i=0;i<4;i++)); do  eval col$i[${j/row/}]=\${$j[$i]} ;done; done
$ echo ${row0[@]}
1 name1 a first
$ echo ${row1[@]}
2 name2 b second
$ echo ${row2[@]}
3 name3 c third
$ echo ${col0[@]}
1 2 3
$ echo ${col1[@]}
name1 name2 name3
$ echo ${col2[@]}
a b c
$ echo ${col3[@]}
first second third

This User Gave Thanks to RudiC For This Post:
# 4  
It would be far better to use this as a stream than to jam them all into shell variables. That is very inefficient and won't be portable.
 

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