Based on two old Max/MSP externals by Cycling'74 that came with the Pluggo installer.
RedALF.atolf(str)
Converts a String into an array of Float values. The floats will be between 0. and 1.
NOTE: There is a maximum string length in supercollider of 8192.
RedALF.lftoa(arr)
Converts an array of Float values into a String. The floats must be between 0. and 1.
NOTE: You will get unexpected values if you try to create your own array from scratch. Always use an array that first have been converted with the atolf method above.