生成器代替迭代器 yield_typescript yield替代-优快云博客

本文链接：https://blog.youkuaiyun.com/gtestcandle/article/details/120457315

本文深入探讨了Python中生成器的使用方法及其优势，并通过具体示例展示了如何利用生成器表达式和惰性求值来提高代码效率。此外，还介绍了自定义迭代器类的方法。

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生成器

def gen_123():
    yield 1
    yield 2
    yield 3

def x():
    print(gen_123)
    [print(i) for i in gen_123()]
    g = gen_123()
    next(g)
    next(g)
    next(g)
def gen_AB():
    print('start')
    yield 'A'
    print('continue')
    yield 'B'
    print('end')
def y():
    [print('-->', c) for c in gen_AB()]

惰性实现


RE_WORD = re.compile('\w+')
class Sentence:
    def __init__(self, text):
        self.text = text
    def __repr__(self):
        return 'Sentence(%s)' % reprlib.repr(self.text)
    def __iter__(self):
        for match in RE_WORD.finditer(self.text):
            yield match.group()

def y():
    s = Sentence('pig and dog')
    # it = iter(s)
    # print(next(it))
    # print(next(it))
    for i in s:
        print(i)
y()

生成器表达式

import re, reprlib
from collections import abc

RE_WORD = re.compile('\w+')
class Sentence:
    def __init__(self, text):
        self.text = text
    def __repr__(self):
        return 'Sentence(%s)' % reprlib.repr(self.text)
    def __iter__(self):
       return (match.group() for match in RE_WORD.finditer(self.text))

def gen_AB():
    print('start')
    yield 'A'
    print('continue')
    yield 'B'
    print('end')

def y():
    res1 = [x*3 for x in gen_AB()]
    [print('-->', i) for i in res1]
    print('----------------')
    res2 = (x*3 for x in gen_AB())  #返回的生成器并不在这使用
    [print('-->', i) for i in res2]
y()