[SOLVED] Array stuck

New2LQ · 04-24-2011, 12:41 AM

Hi everyone. I need help with an array; it continuously loads the first value of a variable. The variable is composed of 4 digits; also, there no comas or spaces separating the digits.
Here's all the code, including output/echoed:

Code:

#Testing formatting input for mm function

FLOOR=1000   #bottom limit of secret number
CEILING=9999 #upper limit of secret number

secret=0   #initializes number
while [ "$secret" -le $FLOOR ]
         #obtaining bottom range
do
  secret=$RANDOM
  let "secret %= $CEILING"
     #number now 4 digits long
done

echo "$secret"

#Placing the number in sn_array

declare -a sn_array  #defines sn_array[ ]

let si=0    #index for sn_array

while [ "$si" -le 3 ]
    do
      sn_array[$si]=${secret:$si:1} 	 	
 	 #control element's location
      ((si +=1))
      	 #increasing index and location
    done

echo $sn_array[0]
echo $sn_array[1]
echo $sn_array[2]
echo $sn_array[3]

output of last run:
5137
5[0]
5[1]
5[2]
5[3]

Thanks in advance.

paulsm4 · 04-24-2011, 02:59 AM

Hi -

Try this "bash" syntax instead:

Code:

sn_array[0]="A"
sn_array[1]="B"
sn_array[2]="C"
echo sn_array[0]: ${sn_array[0]}
echo sn_array[1]: ${sn_array[1]}
echo sn_array[2]: ${sn_array[2]}

Quote:

sn_array[0]: A
sn_array[1]: B
sn_array[2]: C

This is a good link:
http://www.linuxjournal.com/content/bash-arrays

'Hope that helps .. PSM

grail · 04-24-2011, 05:48 AM

I am curious why you use (()) in one part of the code but then use let and things like -le in other parts of the code?

For example:

Code:

FLOOR=1000   #bottom limit of secret number
CEILING=9999 #upper limit of secret number

# this is not required secret=0   #initializes number
while (( secret < FLOOR ))
         #obtaining bottom range
do
  secret=$RANDOM
  (( secret %= CEILING ))
     #number now 4 digits long
done

echo "$secret"

#Placing the number in sn_array

declare -a sn_array  #defines sn_array[ ]

for (( si = 0; si <= 3; si++ ))
do
      sn_array[si]=${secret:$si:1} 	 	
done

echo ${sn_array[0]}
echo ${sn_array[1]}
echo ${sn_array[2]}
echo ${sn_array[3]}

Mainly the only issue you had was missing the curly braces around the echoed items

New2LQ · 04-25-2011, 04:02 AM

Thank you paulsm4 and grail, both of your suggestions were invaluable to the solution! Paul, your suggestion of: sn_array[0]=”A” {etc.} was confusing since “A” wasn’t defined. In incorporated your echo suggestion in the loop, I discovered through the error message that the correct digits were loading into the right spot…great job on that! Next, Grail, the reason for the test brackets was I thought they had to be there…I’m very new with Linux and bash. But your suggestion made my code cleaner! As for the solution…well I had to use n as a variable for the length rather than the digit 1...and off it went.
Thanks to you two, my code not only works, but it’s cleaner.
Thanks from a grateful newbie! Oh, and here’s the working code:

Quote:

#Testing formatting input for mm
FLOOR=1000 #bottom limit of secret number
CEILING=9999 #upper limit of secret number

while ((secret < FLOOR)) #obtaining bottom range
do
secret=$RANDOM
((secret %= CEILING)) #number is now 4 digits long
done

declare -a sn_array #defines sn_array[ ]

for ((si = 0; si <= 3; si++ ))
do
n=1
sn_array[si]=${secret:$si:$n}
done
echo $secret
echo ${sn_array[@]}

Output of last run:
3957
3 9 5 7

grail · 04-25-2011, 04:48 AM

Well here as an alternative for you to mull over

Code:

#Testing formatting input for mm
FLOOR=1000 #bottom limit of secret number
CEILING=9999 #upper limit of secret number

while (( (secret = RANDOM % CEILING ) < FLOOR ));do :;done

declare -a sn_array #defines sn_array[ ]

sn_array=($( echo $secret | awk -F "" '$1=$1' ))

echo $secret
echo ${sn_array[@]}