Lambda
======

.. interactive_code_block::
   :caption: Only eat oysters in months with an 'r'

   months = ['January', 'February', 'March', 'April', 'May', 'June', 'July', 'August', 'September', 'October', 'November', 'December']

   def foo(month):
       return not 'r' in month

   months_without_r = list(filter(foo, months))
   print(months_without_r)


.. interactive_code_block::
   :caption: Only eat oysters in months with an 'r'

   months = ['January', 'February', 'March', 'April', 'May', 'June', 'July', 'August', 'September', 'October', 'November', 'December']

   months_without_r = list(filter(lambda month: not 'r' in month, months))
   print(months_without_r)


Lambda expressions return a function reference
----------------------------------------------

.. interactive_code_block::
   :caption:

   sum = lambda a, b: a + b

   print(sum(12, 34))


..
   Name origin: from 'Lambda calculus' https://en.wikipedia.org/wiki/Lambda_calculus introduced by the mathematician Alonzo Church in the 1930sn