Functional Python

• Recapping: Functional programming maintains no external state and provides data flow synchronisation in the language
• This maps very nicely to the UNIX filter idea. Data flows in and out, with no side affects to the system
  • Note this useful discussion of Haskell vs Unix
• Consider the following script to add numbers, one per line:
  #!/usr/bin/python import sys print sum(int(line) for line in sys.stdin)
• This is both efficient and scalable
  • Efficient because as much iteration as possible is done in compiled code
  • Scalable because only as much memory is used as required for efficiency
• seq 100 | add