I have to work with an output of a Java tool, which returns a map data structure that looks like HashMap<String, ArrayList<String>
. I have to work with BASH and i tried to declare it as an associative array, what is very similar to a map. The declaration of the associative array in bash should be in one line, i try to do this as following.
ARRAY=(["sem1"]=("first name" "second name") ["sem2"]=("third name") ["sem3]=OTHER_LITS)
But this creates the following error:
bash: syntax error near unexpected token `('
I can define this line by line, but i want to have it in one line. How can i define a assoviative array in bash in only one line?
BTW, associative array, dictionary or map - all come into the one abstract data type (let's call it a dictionary).
So, here is the solution for storing array as values in the dictionary of Bash (4+ version).
Note, that array in Bash is a space delimited list of strings (so no any spaces inside the element, i.e. string), so we could write a quoted list:
"firstname middlename secondname"
as a value of the s1
key in our X
dictionary:
declare -A X=(
['s1']="firstname middlename secondname"
['s2']="surname nickname"
['s3']="other"
)
Now we can get the value of the s1
key as array:
declare -a names=(${X[s1]})
Variable names
now contains array:
> echo $names
firstname
> echo ${names[1]}
middlename
> echo ${#names[@]}
3
Finally, your question part where the strings with spaces were shown:
"first name"
, "second name"
Let's do a trick - represent a space as a special symbol sequence (it could be just one symbol), for example, double underscores:
"first__name"
, "second__name"
Declare our dictionary again, but with "escaped" spaces inside array elements:
declare -A X=(
['s1']="first__name middle__name second__name"
['s2']="surname nickname"
['s3']="other"
)
In this case after we get the value of the s1
key as array:
declare -a names=(${X[s1]})
We need to post process our array elements to remove __
the space-replacements to the actual space symbols. To do this we simply use replace commands of Bash strings:
> echo ${names/__/ }
first name
> echo ${names[1]/__/ }
middle name
> echo ${#names[@]}
3
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