In bash, I've an array with values:
declare -A my_array
my_array['key1']='value1'
my_array['key2']='value2'
echo "-----my_array-----"
echo key1: ${my_array['key1']}
echo key2: ${my_array['key2']}
what works well:
-----my_array-----
key1: value1
key2: value2
Although, I'd like to have for a key, a list of values. I've tried something like:
my_array['key2']=('value2.1', 'value2.2')
this gives the error:
my_array['key2']: cannot assign list to array member
What is the Syntax to add a list into an array element and then to access an index values for a key?
CodePudding user response：
It's not possible directly but there is a way to do this via variable expansion, like this:
declare -A my_array
my_array['key1']='value1'
my_array['key2']='value2'
value1="true value1"
value2="true value2"
Check:
$ echo ${!my_array['key1']}
true value1
$ echo ${!my_array['key2']}
true value2
It's more complicated if value* is an array, but also possible:
...
value1=("true value1.1" "true value1.2")
value1=("true value2.1" "true value2.2")
index="${my_array['key1']}[0]"
$ echo "${!index}"
true value2.1
This could be wrapped in a function:
fun(){
local index1=${!1}
local index2="$index1[$2]"
echo "${!index2}"
}
$ fun "my_array['key2']" 1
true value2.2
But IMO you should accept the limitation and rethink the design or consider to use another language.
CodePudding user response：
No. Thechnically, shell variables are only intended to hold strings. But...
Creating array of arrays (even associative), under bash
I will use disk free: df -k output to create associatives array, indexed by device. As tmpfs pseudo device is used for
many differents behaviour, this field must contain a list.
Simpliest way, using special delimiter.
Here I use spaces to delimit contents of fields as they are space delimited by command. Then I use bell special character (\007) to delimit sub arrays.
Here is a sample, using df output, sorting creating lists by device. As result, all tmpfs will be stored together:
declare -A dfVars
{
read _;
while read -r dev _ use free _ mpnt ;do
dfVars["${dev##*/}"] ="$use $((use free)) $mpnt"$'\07'
done
} < <(
LANG=C df -lk
)
You could parse:
for dev in ${!dfVars[@]} ;do
IFS=$'\a\n' read -d '' -ra fields <<<"${dfVars["$dev"]%$'\a'}"
for line in "${fields[@]}";do
read -r use tot mpnt <<<"$line"
printf "%-20s d d %s\n" $dev $use $tot $mpnt
done
done
May output someting like:
tmpfs 0 188928 /dev/shm
tmpfs 19284 188928 /run
tmpfs 4 5120 /run/lock
tmpfs 0 188928 /sys/fs/cgroup
tmpfs 0 37784 /run/user/33
tmpfs 0 37784 /run/user/1001
devtmpfs 0 184596 /dev
mmcblk0p1 23193 42136 /boot
root 115253500 117652696 /
Everything are stored into $dfVars:
declare -p dfVars
declare -A dfVars=([tmpfs]=$'0 188928 /dev/shm\a19284 188928 /run\a4 5120 /run/l
ock\a0 188928 /sys/fs/cgroup\a0 37784 /run/user/33\a0 37784 /run/user/1001\a' [d
evtmpfs]=$'0 184596 /dev\a' [mmcblk0p1]=$'23193 42136 /boot\a' [root]=$'11529034
8 117652696 /\a' )
Stronger: Using nameref for indexing arrays:
With this method, you create independant variables, wich could be array, associative array or even strings...
uuvar() { printf -v "$1" %s d "$2" $(( uuVarCnt));}
declare -A dfVars
{
read _
while read -r dev _ use free _ mpnt ;do
uuvar vname _df_
dfVars["${dev##*/}"] =$vname' '
read -a $vname <<<"$use $((use free)) $mpnt"
done
} < <(LANG=C df -lk)
To parse this:
for dev in ${!dfVars[@]} ;do
for sub in ${dfVars["$dev"]};do
declare -n subDf=$sub
printf "%-20s d d %s\n" "$dev" "${subDf[@]}"
done
done
tmpfs 0 188928 /dev/shm
tmpfs 19284 188928 /run
tmpfs 4 5120 /run/lock
tmpfs 0 188928 /sys/fs/cgroup
tmpfs 0 37784 /run/user/33
tmpfs 0 37784 /run/user/1001
devtmpfs 0 184596 /dev
mmcblk0p1 23193 42136 /boot
root 115254628 117652696 /
Where $dfVars and sub variables look like:
declare -p dfVars uuVarCnt;set | grep ^_df_
declare -A dfVars=([tmpfs]="_df_000000003 _df_000000004 _df_000000005 _df_000000
006 _df_000000008 _df_000000009 " [devtmpfs]="_df_000000002 " [mmcblk0p1]="_df_0
00000007 " [root]="_df_000000001 " )
declare -- uuVarCnt="9"
_df_000000001=([0]="115335328" [1]="117652696" [2]="/")
_df_000000002=([0]="0" [1]="184596" [2]="/dev")
_df_000000003=([0]="0" [1]="188928" [2]="/dev/shm")
_df_000000004=([0]="19284" [1]="188928" [2]="/run")
_df_000000005=([0]="4" [1]="5120" [2]="/run/lock")
_df_000000006=([0]="0" [1]="188928" [2]="/sys/fs/cgroup")
_df_000000007=([0]="23193" [1]="42136" [2]="/boot")
_df_000000008=([0]="0" [1]="37784" [2]="/run/user/33")
_df_000000009=([0]="0" [1]="37784" [2]="/run/user/1001")
Same, but with associative arrays:
declare -A dfVars
uuvar() { printf -v "$1" %s d "$2" $(( uuVarCnt));}
{
read _
while read -r dev _ use free _ mpnt ;do
uuvar vname _df_
dfVars["${dev##*/}"] =$vname' '
declare -A $vname
printf -v $vname[used] %d $use
printf -v $vname[total] %d $((use free))
printf -v $vname[mount\ point] %s "$mpnt"
done
} < <(LANG=C df -lk)
for dev in ${!dfVars[@]} ;do
for sub in ${dfVars["$dev"]} ;do
declare -n subDf=$sub
printf "%-20s d d %s\n" "$dev" \
"${subDf[used]}" "${subDf[total]}" "${subDf["mount point"]}"
done
done
## < snip same output >
Then
declare -p dfVars uuVarCnt;set | grep ^_df_
declare -A dfVars=([tmpfs]="_df_000000003 _df_000000004 _df_000000005 _df_000000
006 _df_000000008 _df_000000009 " [devtmpfs]="_df_000000002 " [mmcblk0p1]="_df_0
00000007 " [root]="_df_000000001 " )
declare -- uuVarCnt="9"
_df_000000001=([used]="115358360" [total]="117652696" ["mount point"]="/" )
_df_000000002=([used]="0" [total]="184596" ["mount point"]="/dev" )
_df_000000003=([used]="0" [total]="188928" ["mount point"]="/dev/shm" )
_df_000000004=([used]="19284" [total]="188928" ["mount point"]="/run" )
_df_000000005=([used]="4" [total]="5120" ["mount point"]="/run/lock" )
_df_000000006=([used]="0" [total]="188928" ["mount point"]="/sys/fs/cgroup" )
_df_000000007=([used]="23193" [total]="42136" ["mount point"]="/boot" )
_df_000000008=([used]="0" [total]="37784" ["mount point"]="/run/user/33" )
_df_000000009=([used]="0" [total]="37784" ["mount point"]="/run/user/1001" )