[SOLVED] problem in handling arrays in bash

himu3118 · 07-05-2010, 05:21 AM

I want to declare an array with fixed size and initialize all the elements to zero. i want all elements of x to be zero and i dont know how to specify the size of array.
also i have problem in comparing values in loops.

my script is as follows:

i=0
let k=0
declare -a x

for U in ${S[@]}
do
for (( T=1276082023 ; $T -le 1276082139 ; (( T++ )) ))
do
if [ $U -le $T ] && [ `expr $U + ${R[$i]}` -ge $T ]
then
x[$k]=$((x[$k]+1))
fi
let k=$k+1
done
k=0
done

Please help me..!!

konsolebox · 07-05-2010, 05:48 AM

here's a suggestion:

Code:

declare -i I=0
declare -a R S LINE; R=() S=()

while read LINE; do
    R[I]=${LINE[7]}   # $(echo "$LINE" | awk 'print $8}')
    S[I]=${LINE[7]}   # $(echo "$LINE" | awk 'print $7}')
    let I++
done < "$FILE"

....
# some examples for now:

# for I in ${!ARRAY[@]}; do
# for V in "${ARRAY[@]}"; do
# VAR[I++]='value'

It's just a part of it 'cause I'm sort of out of time.. later

himu3118 · 07-05-2010, 06:23 AM

now i m using:

for U in ${S[@]}
do
for (( T=1276082023 ; $T -le '1276082139' ; (( T++ )) ))
do
if [ $U -le $T ] && [ `expr $U + ${R[$i]}` -gt $T ]
then
x[$k]=$((x[$k]+1))
fi
let k=$k+1
done
let i=$i+1
k=0
done

then error is coming in second loop. i think there is some string to integer conversion problem. how to correct this problem. and how to initialize all elements of array equal to integer 0.

grail · 07-05-2010, 07:07 AM

Firstly, utilising the [ code ][ \code ] delimeters (without the spaces) will make your code much more readable.

Second, perhaps if you gave us a demo of what is in the file, ie the large numbers, and the goal of the script we may be able to help more?

Lastly, a little consistency would really help with trying to understand your code: (for example)

First post -

Code:

let i=0

Yet you then pull the 'j' variable out of nowhere

From both your posts -

Code:

(( T++ ))

# and then later

let k=$k+1

Again these are the same task, to increase variable by 1, but done in different ways.

Just a thought

himu3118 · 07-05-2010, 09:15 AM

the contents of files which i m reading are:
abc iau aja 97 aj aja 1276082023 5 1276082028
abc iau aja 97 aj aja 1276082023 5 1276082028

i have to read 7th and 8th arg of of each line which i m doing in first part. array S contains large numbers like 1276082023.
i want to compare value of each S with T and S+R with T and accordingly increment x array.

grail · 07-05-2010, 09:29 AM

Not sure where this is going, but assuming I understand you correctly, the following might work:

Code:

awk '{for(t=1276082023; t <= 1276082139; t++)if($7 <= t && $7 + $8 >= t)x[k++]++;k=0}END{for(i=0;i<length(x);i++)print i,x[i]}' file

himu3118 · 07-06-2010, 03:04 AM

thanx.. you almost solved the problem.. thanx a lot.

grail · 07-06-2010, 03:47 AM

Well I believe the awk above does all that was required from the bash script, at least based on the data provided.

Quote:

in that i m not able to compare values like i want to compare values of T

I have 2 suggestions here:
1. Use double square brackets as the single ones some times have peculiar affects
2. Break down your comparisons into single items to see which one is failing

Quote:

also i want to know how to declare array with some intial value as i need to declare x array with all its elements equal to 0

The issue I would see here is you do not know ahead of time how big your array is as 'k' in your script is ever increasing.
Also, if not entered then the default is to be null, are you not able to use this to do whatever test, that has not been shown, that you wish to
do to the array??

himu3118 · 07-06-2010, 04:02 AM

thank you very much. now i have used double quotes and now array thing is also working...