Loop with multiple delimited variables

Shell Programming and Scripting
1

hi,

i need a portion in a audit logging shell script where i have to loop thru multiple variables.
I need some help in accomplishing this. i have 3 variables

var1=1,23,234
var2=a,ab,xyz
var3=0,0,0

the variables will have variables number of values but same length.(3 in this case )

i need to be able to loop thru values in var1 and get the values of all the variables to execute some commands.

while IFS=',' read var1 var2 var2
do
  echo "$var1 1 st value   $var2   first value   $var3 first value"

so for 1 st loop for var1 1 i need to use 1 ,a and 0 in a insert script to some tables. so they need to avaliable in 3 different variables so i can do
insert into table values ($var1, $var2, $var3)

in this case i will get

insert into table (1,'a',0)
insert into table (23,'ab',0)
insert into table 234,'xyz',0)

thanks in advance for some help

2

Please use code tags as required by forum rules!

What does that mean? It obviously contradicts what your sample looks like...?

3

try something like:

var1=1,23,234
var2=a,ab,xyz
var3=0,0,0

IFS="," arr1=($var1)
IFS="," arr2=($var2)
IFS="," arr3=($var3)

seq 0 2 | while read i
do
   echo " insert into table (${arr1[$i]}, '${arr2[$i]}', ${arr3[$i]});"
done
1 Like
4

Howsoever, given the variables as presented in post#1, and bash available, how about

IFS=, read -a A <<<$var1
IFS=, read -a B <<<$var2
IFS=, read -a C <<<$var3
for i in ${!A[@]}; do echo "insert into table (${A[$i]}, ${B[$i]}, ${C[$i]});" ; done
insert into table (1, a, 0);
insert into table (23, ab, 0);
insert into table (234, xyz, 0);

Quotation of the string values left as an exercise for the reader.

5

sorry i meant the number of variable value in each variable will always be the same. if var1 has 3 comma separated values so will var2 and var 3.

---------- Post updated at 12:47 PM ---------- Previous update was at 12:39 PM ----------

thanks rdrtx1 and RudiC.. rdrtx1 can you please explain how seq 0 2 works . i would like to understand this ,,is it based on the number of values in the csv variable? thanks

6 
seq --h
7

So the number of values in the variables may not be the same always. So should I can calculate the length first and use that in the code. This example has 3 for each variable.. but it could be 2 or 4. thanks

---------- Post updated at 01:16 PM ---------- Previous update was at 12:54 PM ----------

thanks I did something like this:

var1=1,23,234,1
var2=a,ab,xyz,z
var3=0,0,0,1

len=`echo $var1 | awk -F '[,]' '{print  NF}'`
echo "$len"

--4

8

${#A[@]} is array A's element count, ${!A[@]} lists all the indices into array A.

For the quoting of string variables, try

QUS() { FMT="%s"; [[ $1 =~ [^[:digit:]] ]] && FMT="'%s'"; printf $FMT $1; }
for i in ${!A[@]}; do echo "insert into table ($(QUS ${A[$i]}), $(QUS ${B[$i]}), $(QUS ${C[$i]}));" ; done
insert into table (1, 'a', 0);
insert into table (23, 'ab', 0);
insert into table (234, 'xyz', '1a2b');
9

IFS cannot be set local to an array assignment. So you would need to set it globally and use something like:

oldIFS=$IFS
IFS=,
arr1=($var1) arr2=($var2) arr3=($var3)
IFS=$oldIFS

Why use an (outdated) external program ( seq ) and a pipe when we can use shell syntax

for i in 0 1 2
do

In bash, zsh and ksh93 you can use:

for i in {0..2}
do

or

for (( i=0; i<=2; i++))
do

Not important, but perhaps interesting is that there is no need to use a $ sign for a variable reference used as an index to an array:

echo "insert into table (${arr1}, '${arr2}', ${arr3});"
10

thank you all for your valuable inputs. i can incorporate this now:

code

#!/bin/sh

var1=1,23,234,1
var2=a,ab,xyz,z
var3=0,0,0,1
var4=0,0,0,1


len=`echo $var1 | awk -F '[,]' '{print  NF-1}'`
echo "$len"

oldIFS=$IFS
IFS=,
arr1=($var1) arr2=($var2) arr3=($var3)  arr4=($var4)
IFS=$oldIFS

for (( i=0; i<=3; i++))
do
  echo " insert into table (${arr1[$i]},${arr2[$i]},${arr3[$i]},${arr4[$i]});"
done
11

You are welcome. To add, instead of

len=`echo $var1 | awk -F '[,]' '{print  NF-1}'`

one could also use plain shell, without external programs:

len=${#arr1[@]}

after arr1 is set...

--
=> Please use code tags next time for code and data <=