How can I join elements of an array in Bash?

Question

If I have an array like this in Bash:

FOO=( a b c )

How do I join the elements with commas? For example, producing a,b,c.

Answer 1

In case the elements you want to join is not an array just a space separated string, you can do something like this:

foo="aa bb cc dd"
bar=`for i in $foo; do printf ",'%s'" $i; done`
bar=${bar:1}
echo $bar
    'aa','bb','cc','dd'

for example, my use case is that some strings are passed in my shell script and I need to use this to run on a SQL query:

./my_script "aa bb cc dd"

In my_script, I need to do "SELECT * FROM table WHERE name IN ('aa','bb','cc','dd'). Then above command will be useful.