Mutable list or array structure in Bash? How can I easily append to it?

Question

I'm trying to collect string values in a bash script. What's the simplest way that I can append string values to a list or array structure such that I can echo them out at the end?

Answer 1

foo=(a b c)
foo=("${foo[@]}" d)
for i in "${foo[@]}"; do echo "$i" ; done

Answer 2

The rather obscure syntax for appending to the end of an array in bash is:

myarr[${#myarr[*]}]=”$newitem”

Answer 3

To add to what Ignacio has suggested in another answer:

foo=(a b c)
foo=("${foo[@]}" d) # push element 'd'

foo[${#foo[*]}]="e" # push element 'e'

for i in "${foo[@]}"; do echo "$i" ; done

Answer 4

$ arr=(1 2 3)
$ arr+=(4)
$ echo ${arr[@]}
1 2 3 4

Since Bash uses sparse arrays, you shouldn't use the element count ${#arr} as an index. You can however, get an array of indices like this:

$ indices=(${!arr[@]})

Answer 5

$ for i in "string1" "string2" "string3"
> do
> array+=($i)
> done
$ echo ${array[@]}
string1 string2 string3