shell script array won't populate from for loop - arrays

Question

Can anyone tell me why this array creation: cccr[$string_1]=$string_2 #doesn't work?
#!/bin/bash
firstline='[Event "Marchand Open"][Site "Rochester NY"][Date "2005.03.19"][Round "1"][White "Smith, Igor"][Black "Jones, Matt"][Result "1-0"][ECO "C01"][WhiteElo "2409"][BlackElo "1911"]'
unset cccr
declare -A cccr
(IFS='['; for word in $firstline; do
string_1=$(echo $word | cut -f1 -d'"' | tr -d ' ')
string_2=$( echo $word | cut -f2 -d'"' )
if [ ! -z $string_1 ]; then # If $string_1 is not empty
cccr[$string_1]=$string_2 # why doesn't this line work?
fi
done)
echo ${cccr[Event]} # echos null string

Answer 1

It happens because the value of string_1 is empty at the first iteration.
Example :
#!/bin/bash
firstline='[Event "Marchand Open"][Site "Rochester NY"][Date "2005.03.19"][Round "1"][White "Smith, Igor"][Black "Jones, Matt"][Result "1-0"][ECO "C01"][WhiteElo "2409"][BlackElo "1911"]'
unset cccr
declare -A cccr
(IFS='['; for word in $firstline; do
string_1=$( echo $word | cut -f1 -d'"' )
string_2=$( echo $word | cut -f2 -d'"' )
echo "$string_1 - $string_2"
#cccr[$string_1]=$string_2
done)
Output :
- # Problem !
Event - Marchand Open
Site - Rochester NY
...
You have to modify your script to prevent the value of being empty.
A very simple workaround is to check the value of string_1 before using it.
Example :
# ...
string_1=$( echo $word | cut -f1 -d'"' )
string_2=$( echo $word | cut -f2 -d'"' )
if [ ! -z $string_1 ]; then # If $string_1 is not empty
echo "$string_1 - $string_2"
cccr[$string_1]=$string_2
fi
# ...
From the man page of [
-z STRING
the length of STRING is zero
Output :
Event - Marchand Open
Site - Rochester NY
# ... No problem
EDIT
BTW, if look at the value of string_1, you will see that the value is Event' ' and not Event (there's a whitespace at the end of Event)
So cccr[Event] does not exist, but cccr[Event ] exists.
To fix that, you can delete the whitespaces in string_1 :
string_1=$(echo $word | cut -f1 -d'"' | tr -d ' ') # tr -d ' ' deletes all the whitespaces
EDIT 2
I forgot to tell you that it's normal if it does not work. Indeed, the loop is executed in a subshell environment. So the array is filled in the subshell, but not in the current shell.
From the man page of bash :
(list) list is executed in a subshell environment (see COMMAND EXECUTION ENVIRONMENT below). Variable
assignments and builtin commands that affect the shell's environment do not remain in effect
after the command completes. The return status is the exit status of list.
So there are 2 solutions :
1. Don't run the loop in a subshell (remove the parentheses).
# ...
OLDIFS=$IFS
IFS='['
for word in $firstline; do
string_1=$(echo $word | cut -f1 -d'"' | tr -d ' ')
string_2=$(echo $word | cut -f2 -d'"')
if [ ! -z $string_1 ]; then
cccr[$string_1]=$string_2
fi
done
IFS=$OLDIFS
echo "Event = ${cccr[Event]}"
echo "Site = ${cccr[Site]}"
Output :
Event = Marchand Open
Site = Rochester NY
2. Use your array in the subshell.
# ...
(IFS='['
for word in $firstline; do
string_1=$(echo $word | cut -f1 -d'"' | tr -d ' ')
string_2=$(echo $word | cut -f2 -d'"')
if [ ! -z $string_1 ]; then # If $string_1 is not empty
cccr[$string_1]=$string_2
fi
done
echo "Event = ${cccr[Event]}"
echo "Site = ${cccr[Site]}"
)
Output :
Event = Marchand Open
Site = Rochester NY