ruby - string in ddmmyyyy format to to date -

i have folder contains bunch of folders naming convention of mmddyyyy (for example 04102013, 04092013, etc.). have text file contains these paths , have programed in ruby array strips out path left date (however believe stored sting).

what need take dates in array , add amount of days them. amount of days static , same value needs applied across board in array. on 8th line getting invalid date (argumenterror). end result needs array +7 days every item in array. right can't values date format.

require 'date' myarray = io.readlines "/path/to/myfile.txt" myarray.each |s|   s.gsub!('/path/to/my/dated/folders/', '') end print myarray   myarray.map! {date.strptime("%m%d%y")} # myarray.map! {+(7)} print myarray 

try:

myarray.map!{|s| date.strptime(s, '%m%d%y') + 7}