Adopted from the "Bash: cd to last path after exit" example in the man page for ranger(1).

Zsh: change directory using ranger

   ranger-cd() {
     tempfile=$(mktemp)
     ranger --choosedir="$tempfile" "${@:-$(pwd)}" < $TTY
     test -f "$tempfile" &&
     if [ "$(cat -- "$tempfile")" != "$(echo -n `pwd`)" ]; then
       cd -- "$(cat "$tempfile")"
     fi
     rm -f -- "$tempfile"
   }

   # This binds Ctrl-O to ranger-cd:
   zle -N ranger-cd
   bindkey '^o' ranger-cd