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Dynamic variable assignment

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# 1  
Old 11-22-2010
Dynamic variable assignment
Hi all,

I’m very new to UNIX programming. I have a question on dynamic variable

1. I’m having delimited file (only one row). First of all, I want to count number of columns based on delimiter. Then I want to create number of variables equal to number of fields.

Say number of fields equal to N

Code:
N=`cat ffvldtn_test.txt | awk 'BEGIN{FS="|"};{print NF}'`

From the above, I’m getting the fields count equal to five.

Code:
n=1
 
 
while [ $n -le $NF ];
do
 
eval "eval_var=\$var${n}"
eval_var=`cat ffvldtn_test.txt | cut -d '|' -f${n}`
  echo "var${n}=${eval_var}"
((n=n+1))
done


The above script is working as expected. But the real thing is that I can’t re call the variables when I required in the script.

Code:
echo $var1
echo $var2
echo $var3
echo $var4
echo $var5

all are giving blank…

please help out to fix this

Moderator's Comments:
Mod Comment Please use code tags. You've got an PM explaining the details
Last edited by pludi; 11-22-2010 at 09:03 AM..
# 2  
Old 11-22-2010
I guess "|" is your field separator, right?
try this:
Code:
read -a arr <<< `sed 's/|/ /g' | your_input_file_here`
for e in ${arr[@]}; do
    echo $e
done

# 3  
Old 11-22-2010
Quote:
Originally Posted by kevintse
I guess "|" is your field separator, right?
try this:
Code:
read -a arr <<< `sed 's/|/ /g' | your_input_file_here`
for e in ${arr[@]}; do
    echo $e
done


yes kevintse."|" is my field separator...thanks for ur reply...let u know if its work

---------- Post updated at 07:38 AM ---------- Previous update was at 07:32 AM ----------

kevintse,

its not at all working...better u chnage my code and post it...
# 4  
Old 11-22-2010
Why don't you use arrays?

An example how to use arrays and "dynamic variables" if you persist to use that:
Code:
set $(awk 'BEGIN{FS="|"};{print NF}' ffvldtn_test.txt)

n=1

for i in $@
do
  arr[$n]=${i}		# fill array
  eval "var_${n}=${i}"	# fill dynamic variable
  n=$(( $n + 1 ))
done

echo arr[1]
echo arr[2]
echo arr[3]
echo arr[4]
echo arr[5]

echo $var1
echo $var2
echo $var3
echo $var4
echo $var5

# 5  
Old 11-22-2010
Quote:
Originally Posted by mkarthykeyan
yes kevintse."|" is my field separator...thanks for ur reply...let u know if its work

---------- Post updated at 07:38 AM ---------- Previous update was at 07:32 AM ----------

kevintse,

its not at all working...better u chnage my code and post it...
Why, what error messages did you get?

can you run this code on your machine:
Code:
#!/bin/bash

read -a arr <<< `echo "hello|world|test" | sed 's/|/ /g'`
for e in ${arr[@]}; do
    echo $e
done
#in my test, it prints
hello
world
test

# 6  
Old 11-23-2010
$ sh test_1
test_1[2]: syntax error at line 2 : `<' unexpected
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