Comments on: bash array operations

By: DemonWeasel

DemonWeasel — Fri, 02 Oct 2009 00:13:46 +0000

and...here's the real solution...

function remel() {
array=$1
i=$2
if [ $i -ne 0 ]; then
eval "$array"="( `eval echo ${$array[@]:0:$i} ${$array[@]:$(($i + 1))}` )";
else
eval "$array"="( `eval echo ${$array[@]:$(($i + 1))}` )";
fi
}

#to use it:
arr=( a b c d )
echo ${arr[@]}
echo ${arr[1]}
#now it actually just removes the element...
remel arr 1
echo ${arr[@]}
echo ${arr[1]}

By: DemonWeasel

DemonWeasel — Thu, 01 Oct 2009 23:32:33 +0000

or if you want a more standard syntax of taking an array in as a parameter

function remel(){
array=( $@ )
let ind=${#array[@]}-1
i=${array[$ind]}
unset array[$ind]
if [ $i -ne 0 ]; then
array=( ${array[@]:0:$i} ${array[@]:$(($i + 1))} )
else
array=( ${array[@]:$(($i + 1))} )
fi
echo ${array[@]}
}

#to use it:
arr=( a b c d )
echo ${arr[@]}
echo ${arr[1]}
#to remove element 1 set the array equal to an array of the output
arr=( `remel ${arr[@]} 1` )
echo ${arr[@]}
echo ${arr[1]}

By: DemonWeasel

DemonWeasel — Thu, 01 Oct 2009 22:48:07 +0000

#a function to create a new array minus the specified element

function remel() {
array=( `eval echo '${'$1"[@]"'}'` )
i=$2
#remove EL from array
if [ $i -ne 0 ]; then
array=( ${array[@]:0:$i} ${array[@]:$(($i + 1))} )
else
array=( ${array[@]:$(($i + 1))} )
fi
echo ${array[@]}
}

#to use it:
arr=( a b c d )
echo ${arr[@]}
echo ${arr[1]}
#to remove element 1 set the array equal to an array of the output
arr=( `remel arr 1` )
echo ${arr[@]}
echo ${arr[1]}

By: cori_chenxx

cori_chenxx — Sun, 23 Aug 2009 23:25:03 +0000

unset command is enough

By:

Fri, 29 Aug 2008 06:26:47 +0000

#remove i from array unset array[$i] array=( ${array[@]} )

By:

Sun, 25 Mar 2007 15:41:06 +0000

so looking at the tip found here:
http://www.tech-recipes.com/bourne_shell_scripting_tips910.html

:oops: works as long as you do not try and remove element 0. Look at just this part:
${array[@]:0:$i}
and you will notice the array is rebuilt using items 0 through $i. The 0 will cause element 0 to stay in the array even if i=0
Does anyone have a better fix than this:
#remove i from array if [ $i -ne 0 ]; then array=( ${array[@]:0:$i} ${array[@]:$(($i + 1))} ) else array=( ${array[@]:$(($i + 1))} ) fi