set builder notation generator

Design Mode note generator (Builder) mode Builder // Builder mode --- object Creation Mode /* 1: Intention: separates the construction of a complex object from its representation, so that different representations can be created during the same construction process. 2: Motivation 3: Applicability: 1> when creating c

execution process, encounter yield is interrupted, the next time continue to execute. After 3 yield, no yield can be executed, so the 4th call to Next () is an error.Returning to the FIB example, we constantly call yield during the loop, and we are constantly interrupted. Of course, you have to set a condition for the loop to exit the loop, or it will produce an infinite sequence.Similarly, after changing a function to

example, we constantly call yield during the loop, and we interrupt. Of course, set a condition to the loop to exit the loop, or it will produce an infinite series out. Again, after changing the function to generator, we basically never invoke it with next (), but instead use the For loop to iterate: Copy Code code as follows: >>> for N in fib (6): ... print n ... 1 1 2 3 5

Generator Generator generator: A mechanism for calculating one side of the loop.A generator is a special program that can be used to control the iterative behavior of loops. The builder in Python is one of the iterators that use the yield return value function, which i

What is a generator:As long as there is a yield keyword inside the function, the result (the generator address) of the function name () is the generator,Re-calling function does not execute function internal codeThe generator itself has the _iter_ he _next_ function (i.e. the generator is an iterator)Why Use Generators

course, in fact, rarely use next (), we directly with the For loop can traverse a generator, in fact, the internal implementation of the For loop is to call next ().Generators can avoid unnecessary computations, improve performance, and save space for an infinite loop (infinitely large) data structure.2.the concept of an iterative object (iterable) and an iterator (Iterator)An object that can directly act on for a loop is called an iterative object:

List Builder# Common is the range () to create a list of numbers >>>[x*x for x in range (10)][0, 1, 4, 9, 16, 25, 36, 49, 64, 81]# back can also be added with a judgment statement >>>[ X*x for x in range (ten) if x%2 = = 0][0, 4, 16, 36, 64]# characters can also play this way >>> [M + N for m in ' ABC ' for n ' XYZ ' [' AX ', ' A Y ', ' AZ ', ' BX ', ' by ', ' BZ ', ' CX ', ' CY ', ' CZ ']　　Generator#

3.1. dictionary generative, set generative, and generator, 3.1 generativeDictionary generation: Like the list generator, the dictionary generator is used to quickly generate a dictionary. The difference is that the dictionary requires two values. #d = {key: value for (key, value) in iterable}d1 = {'x': 1, 'y': 2,