Python Learning D13 iterator Generator list deduction builder expression

02, iterator
    Objects that can be iterated:
Internal containing __iter__  follows an iterative protocol

# Print (dir (' 123 '))  # ' __iter__ '#  print (' __iter__ ' in Dir ([1, 2, 3])#  Print (' __iter__ ' in dir ({' name ': ' Alex '})#  print (' __iter__ ' in dir ({' name '})#) #  Print (' __iter__ ' in Dir ((1, 2, 3))#  print (' __iter__ ' in Dir (1))  # False# c15> print (' __iter__ ' in Dir (True))  # False

 iterator: An iterative object. __iter__ () can be converted to an iterator that satisfies the iterator protocol

internally containing __iter__ and __next__
determine if the __iter__ is not in Dir (object)
isinstance ()
save memory. 
inertia mechanism. 
unidirectional irreversible. 
mechanism for the FOR loop:
 while
Pass


can iterate over objects
iterators
difference between the two
simulating for loop mechanism

03, Generator
is essentially an iterator, built with Python code. 
Generator Definition
the builder's notation
yield
Send

Python learning D13 iterator builder list deduction builder expression