fr [mailto:clement.ow / asia.bnpparibas.com] 
# All i managed to convert is(using .to_s):
# str[0] = "xlsini20080326"
# str[1] = "gifxlsrb"
# but i want to convert each array into a string, something like
# str[0] = "xls,ini,20080326"
# str[1] = "gif,xls,rb"


botp@botp-desktop:~$ qri array.join
------------------------------------------------------------- Array#join
     array.join(sep=$,)    -> str
------------------------------------------------------------------------
     Returns a string created by converting each element of the array
     to a string, separated by sep.

        [ "a", "b", "c" ].join        #=> "abc"
        [ "a", "b", "c" ].join("-")   #=> "a-b-c"

botp@botp-desktop:~$ irb
irb(main):003:0> ex[0] = ["xls", "ini", "20080326"]
=> ["xls", "ini", "20080326"]
irb(main):005:0> str[0]=ex[0].join(",")
=> "xls,ini,20080326"

kind regards -botp