On 8/1/2013 11:35 AM, Alexander Belopolsky wrote:
Here is one use-case where .. = lambda .. cannot be replaced with def ..
op['add'] = lambda x,y: x+y
op['mul'] = lambda x, y: x*y
Yes, you are binding the functions to named slots, not to names, so not
covered by the PEP. Once might still want to replace the expressions
themselves, at the cost of more typing, for the advantage of better
representations.
op = { 'add': lambda x,y: x*y, 'mul': lambda x, y: x+y}
print(op) # no apparent problem
# {'add': <function <lambda> at 0x000000000227F730>,
# 'mul': <function <lambda> at 0x00000000033867B8>}
def add(x, y): return x + y
def mul(x, y): return x * y
# These can be unittested individually
op = {'add': mul, 'mul': add} # mistake easily seen in original code
print(op)
# {'add': <function mul at 0x0000000003440950>,
# 'mul': <function add at 0x00000000034408C8>}
# problem apparent to user who import this object and prints it when
code fails
If op has 20 such functions, names become even more of an advantage
--
Terry Jan Reedy
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