ruby将16进制转10进制有关问题

ruby将16进制转10进制问题
有一串16进制字符串，如“01 01 01 01”、“a1 01 b1 01”等

需要将其转成十进制，如“01 01 01 01”---> “1010101” ----> 16843009
  “a1 01 b1 01”---> “a101b101” ----> 2701242625

如何操作?
请教各位达人～～～


------解决方案--------------------
/*
 * call-seq:
 * str.to_i(base=10) -> integer
 *
 * Returns the result of interpreting leading characters in <i>str</i> as an
 * integer base <i>base</i> (between 2 and 36). Extraneous characters past the
 * end of a valid number are ignored. If there is not a valid number at the
 * start of <i>str</i>, <code>0</code> is returned. This method never raises an
 * exception when <i>base</i> is valid.
 *
 * "12345".to_i #=> 12345
 * "99 red balloons".to_i #=> 99
 * "0a".to_i #=> 0
 * "0a".to_i(16) #=> 10
 * "hello".to_i #=> 0
 * "1100101".to_i(2) #=> 101
 * "1100101".to_i(8) #=> 294977
 * "1100101".to_i(10) #=> 1100101
 * "1100101".to_i(16) #=> 17826049
 */