Convert array type variable to string type with space delimiter

For completeness, while the "${array[*]}" Korn syntax (extended from the Bourne "$*" special parameter) would also work in zsh, in zsh, you may want to use the j (for join) parameter expansion flag instead which allows you to use any arbitrary joining string and doesn't need to rely on a global parameter like $IFS:

$ a=(foo bar)
$ echo ${(j[:::])a}
foo:::bar

Note that for "${a[*]}", ksh (both ksh93 and mksh) join on the first byte of $IFS instead of first character. That matters for multi-byte characters like:

$ ksh -c 'a=(foo bar); IFS="⇅"; echo "${a[*]}"'
foo�bar
$ mksh -c 'a=(foo bar); IFS="⇅"; echo "${a[*]}"'
foo�bar
$ mksh -o utf8-mode -c 'a=(foo bar); IFS="⇅"; echo "${a[*]}"'
foo�bar

(where that � is how my terminal emulator rendered the first byte (0xe2) of that ⇅ character which by itself doesn't form a valid character).

Other Korn-like shells with array support are OK:

$ bash -c 'a=(foo bar); IFS="⇅"; echo "${a[*]}"'
foo⇅bar
$ zsh -c 'a=(foo bar); IFS="⇅"; echo "${a[*]}"'
foo⇅bar
$ yash -c 'a=(foo bar); IFS="⇅"; echo "${a[*]}"'
foo⇅bar