![\"\"](\"https:\/\/egonlin.com\/wp-content\/uploads\/2022\/03\/\u751f\u6210\u56681.jpg\")
<\/div><\/p>\n\u4e00 \u751f\u6210\u5668\u4e0eyield<\/h1>\n
![\"\"](\"https:\/\/egonlin.com\/wp-content\/uploads\/2022\/03\/\u6076\u641e\u56fe49.jpg\")
<\/div><\/p>\n\u82e5\u51fd\u6570\u4f53\u5305\u542byield\u5173\u952e\u5b57\uff0c\u518d\u8c03\u7528\u51fd\u6570\uff0c\u5e76\u4e0d\u4f1a\u6267\u884c\u51fd\u6570\u4f53\u4ee3\u7801\uff0c\u5f97\u5230\u7684\u8fd4\u56de\u503c\u5373\u751f\u6210\u5668\u5bf9\u8c61<\/p>\n
>>> def my_range(start,stop,step=1):\n... print('start...')\n... while start < stop:\n... yield start\n... start+=step\n... print('end...')\n... \n>>> g=my_range(0,3)\n>>> g\n<generator object my_range at 0x104105678><\/code><\/pre>\n\u751f\u6210\u5668\u5185\u7f6e\u6709__iter__\u548c__next__\u65b9\u6cd5\uff0c\u6240\u4ee5\u751f\u6210\u5668\u672c\u8eab\u5c31\u662f\u4e00\u4e2a\u8fed\u4ee3\u5668<\/p>\n
>>> g.__iter__\n<method-wrapper '__iter__' of generator object at 0x1037d2af0>\n>>> g.__next__\n<method-wrapper '__next__' of generator object at 0x1037d2af0><\/code><\/pre>\n\u63d2\u56fe\uff1a\u6076\u641e\u56fe50<\/p>\n
![\"\u6076\u641e\u56fe50\"](\"data:image\/svg+xml;base64,PCEtLUFyZ29uTG9hZGluZy0tPgo8c3ZnIHdpZHRoPSIxIiBoZWlnaHQ9IjEiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyIgc3Ryb2tlPSIjZmZmZmZmMDAiPjxnPjwvZz4KPC9zdmc+\")
<\/div><\/p>\n\u56e0\u800c\u6211\u4eec\u53ef\u4ee5\u7528next(\u751f\u6210\u5668)\u89e6\u53d1\u751f\u6210\u5668\u6240\u5bf9\u5e94\u51fd\u6570\u7684\u6267\u884c\uff0c<\/p>\n
>>> next(g) # \u89e6\u53d1\u51fd\u6570\u6267\u884c\u76f4\u5230\u9047\u5230yield\u5219\u505c\u6b62,\u5c06yield\u540e\u7684\u503c\u8fd4\u56de\uff0c\u5e76\u5728\u5f53\u524d\u4f4d\u7f6e\u6302\u8d77\u51fd\u6570\nstart...\n0\n>>> next(g) # \u518d\u6b21\u8c03\u7528next(g)\uff0c\u51fd\u6570\u4ece\u4e0a\u6b21\u6682\u505c\u7684\u4f4d\u7f6e\u7ee7\u7eed\u6267\u884c\uff0c\u76f4\u5230\u91cd\u65b0\u9047\u5230yield...\n1\n>>> next(g) # \u5468\u800c\u590d\u59cb...\n2\n>>> next(g) # \u89e6\u53d1\u51fd\u6570\u6267\u884c\u6ca1\u6709\u9047\u5230yield\u5219\u65e0\u503c\u8fd4\u56de\uff0c\u5373\u53d6\u503c\u5b8c\u6bd5\u629b\u51fa\u5f02\u5e38\u7ed3\u675f\u8fed\u4ee3\nend...\nTraceback (most recent call last):\n File "<stdin>", line 1, in <module>\nStopIteration<\/code><\/pre>\n<\/div><\/p>\n\u65e2\u7136\u751f\u6210\u5668\u5bf9\u8c61\u5c5e\u4e8e\u8fed\u4ee3\u5668\uff0c\u90a3\u4e48\u5fc5\u7136\u53ef\u4ee5\u4f7f\u7528for\u5faa\u73af\u8fed\u4ee3\uff0c\u5982\u4e0b\uff1a<\/p>\n
>>> for i in countdown(3):\n... print(i)\n... \ncountdown start\n3\n2\n1\nDone!<\/code><\/pre>\n\u6709\u4e86yield\u5173\u952e\u5b57\uff0c\u6211\u4eec\u5c31\u6709\u4e86\u4e00\u79cd\u81ea\u5b9a\u4e49\u8fed\u4ee3\u5668\u7684\u5b9e\u73b0\u65b9\u5f0f\u3002yield\u53ef\u4ee5\u7528\u4e8e\u8fd4\u56de\u503c\uff0c\u4f46\u4e0d\u540c\u4e8ereturn\uff0c\u51fd\u6570\u4e00\u65e6\u9047\u5230return\u5c31\u7ed3\u675f\u4e86\uff0c\u800cyield\u53ef\u4ee5\u4fdd\u5b58\u51fd\u6570\u7684\u8fd0\u884c\u72b6\u6001\u6302\u8d77\u51fd\u6570\uff0c\u7528\u6765\u8fd4\u56de\u591a\u6b21\u503c<\/p>\n
<\/div><\/p>\n\u4e8c yield\u8868\u8fbe\u5f0f\u5e94\u7528<\/h1>\n
\u5728\u51fd\u6570\u5185\u53ef\u4ee5\u91c7\u7528\u8868\u8fbe\u5f0f\u5f62\u5f0f\u7684yield<\/p>\n
>>> def eater():\n... print('Ready to eat')\n... while True:\n... food=yield\n... print('get the food: %s, and start to eat' %food)\n... <\/code><\/pre>\n\u53ef\u4ee5\u62ff\u5230\u51fd\u6570\u7684\u751f\u6210\u5668\u5bf9\u8c61\u6301\u7eed\u4e3a\u51fd\u6570\u4f53send\u503c\uff0c\u5982\u4e0b<\/p>\n
>>> g=eater() # \u5f97\u5230\u751f\u6210\u5668\u5bf9\u8c61\n>>> g\n<generator object eater at 0x101b6e2b0>\n>>> next(e) # \u9700\u8981\u4e8b\u5148\u201d\u521d\u59cb\u5316\u201d\u4e00\u6b21\uff0c\u8ba9\u51fd\u6570\u6302\u8d77\u5728food=yield\uff0c\u7b49\u5f85\u8c03\u7528g.send()\u65b9\u6cd5\u4e3a\u5176\u4f20\u503c\nReady to eat\n>>> g.send('\u5305\u5b50')\nget the food: \u5305\u5b50, and start to eat\n>>> g.send('\u9e21\u817f')\nget the food: \u9e21\u817f, and start to eat<\/code><\/pre>\n\u9488\u5bf9\u8868\u8fbe\u5f0f\u5f62\u5f0f\u7684yield\uff0c\u751f\u6210\u5668\u5bf9\u8c61\u5fc5\u987b\u4e8b\u5148\u88ab\u521d\u59cb\u5316\u4e00\u6b21\uff0c\u8ba9\u51fd\u6570\u6302\u8d77\u5728food=yield\u7684\u4f4d\u7f6e\uff0c\u7b49\u5f85\u8c03\u7528g.send()\u65b9\u6cd5\u4e3a\u51fd\u6570\u4f53\u4f20\u503c\uff0cg.send(None)\u7b49\u540c\u4e8enext(g)\u3002<\/p>\n
<\/div><\/p>\n\u200b \u6211\u4eec\u53ef\u4ee5\u7f16\u5199\u88c5\u9970\u5668\u6765\u5b8c\u6210\u4e3a\u6240\u6709\u8868\u8fbe\u5f0f\u5f62\u5f0fyield\u5bf9\u5e94\u751f\u6210\u5668\u7684\u521d\u59cb\u5316\u64cd\u4f5c\uff0c\u5982\u4e0b<\/p>\n
def init(func):\n def wrapper(*args,**kwargs):\n g=func(*args,**kwargs)\n next(g)\n return g\n return wrapper\n\n@init\ndef eater():\n print('Ready to eat')\n while True:\n food=yield\n print('get the food: %s, and start to eat' %food)<\/code><\/pre>\n\u8868\u8fbe\u5f0f\u5f62\u5f0f\u7684yield\u4e5f\u53ef\u4ee5\u7528\u4e8e\u8fd4\u56de\u591a\u6b21\u503c\uff0c\u5373\u53d8\u91cf\u540d=yield \u503c<\/code>\u7684\u5f62\u5f0f\uff0c\u5982\u4e0b<\/p>\n>>> def eater():\n... print('Ready to eat')\n... food_list=[]\n... while True:\n... food=yield food_list\n... food_list.append(food)\n... \n>>> e=eater()\n>>> next(e)\nReady to eat\n[]\n>>> e.send('\u84b8\u7f8a\u7f94')\n['\u84b8\u7f8a\u7f94']\n>>> e.send('\u84b8\u718a\u638c')\n['\u84b8\u7f8a\u7f94', '\u84b8\u718a\u638c']\n>>> e.send('\u84b8\u9e7f\u5c3e\u513f')\n['\u84b8\u7f8a\u7f94', '\u84b8\u718a\u638c', '\u84b8\u9e7f\u5c3e\u513f']<\/code><\/pre>\n<\/div><\/p>\n\u4e09 \u4e09\u5143\u8868\u8fbe\u5f0f\u3001\u5217\u8868\u751f\u6210\u5f0f\u3001\u751f\u6210\u5668\u8868\u8fbe\u5f0f<\/h1>\n3.1 \u4e09\u5143\u8868\u8fbe\u5f0f<\/h2>\n
\u4e09\u5143\u8868\u8fbe\u5f0f\u662fpython\u4e3a\u6211\u4eec\u63d0\u4f9b\u7684\u4e00\u79cd\u7b80\u5316\u4ee3\u7801\u7684\u89e3\u51b3\u65b9\u6848\uff0c\u8bed\u6cd5\u5982\u4e0b<\/p>\n
res = \u6761\u4ef6\u6210\u7acb\u65f6\u8fd4\u56de\u7684\u503c if \u6761\u4ef6 else \u6761\u4ef6\u4e0d\u6210\u7acb\u65f6\u8fd4\u56de\u7684\u503c<\/code><\/pre>\n\u9488\u5bf9\u4e0b\u8ff0\u573a\u666f<\/p>\n
def max2(x,y):\n if x > y:\n return x\n else:\n return y\n\nres = max2(1,2)<\/code><\/pre>\n\u7528\u4e09\u5143\u8868\u8fbe\u5f0f\u53ef\u4ee5\u4e00\u884c\u89e3\u51b3<\/p>\n
x=1\ny=2\nres = x if x > y else y # \u4e09\u5143\u8868\u8fbe\u5f0f<\/code><\/pre>\n<\/div><\/p>\n3.2 \u5217\u8868\u751f\u6210\u5f0f<\/h2>\n
\u5217\u8868\u751f\u6210\u5f0f\u662fpython\u4e3a\u6211\u4eec\u63d0\u4f9b\u7684\u4e00\u79cd\u7b80\u5316\u4ee3\u7801\u7684\u89e3\u51b3\u65b9\u6848\uff0c\u7528\u6765\u5feb\u901f\u751f\u6210\u5217\u8868\uff0c\u8bed\u6cd5\u5982\u4e0b<\/p>\n
[expression for item1 in iterable1 if condition1\nfor item2 in iterable2 if condition2\n...\nfor itemN in iterableN if conditionN\n]\n\n#\u7c7b\u4f3c\u4e8e\nres=[]\nfor item1 in iterable1:\n if condition1:\n for item2 in iterable2:\n if condition2\n ...\n for itemN in iterableN:\n if conditionN:\n res.append(expression)<\/code><\/pre>\n\u9488\u5bf9\u4e0b\u8ff0\u573a\u666f<\/p>\n
egg_list=[]\nfor i in range(10):\n egg_list.append('\u9e21\u86cb%s' %i)<\/code><\/pre>\n\u7528\u5217\u8868\u751f\u6210\u5f0f\u53ef\u4ee5\u4e00\u884c\u89e3\u51b3<\/p>\n
egg_list=['\u9e21\u86cb%s' %i for i in range(10)]<\/code><\/pre>\n<\/div><\/p>\n3.3 \u751f\u6210\u5668\u8868\u8fbe\u5f0f<\/h2>\n
\u521b\u5efa\u4e00\u4e2a\u751f\u6210\u5668\u5bf9\u8c61\u6709\u4e24\u79cd\u65b9\u5f0f\uff0c\u4e00\u79cd\u662f\u8c03\u7528\u5e26yield\u5173\u952e\u5b57\u7684\u51fd\u6570\uff0c\u53e6\u4e00\u79cd\u5c31\u662f\u751f\u6210\u5668\u8868\u8fbe\u5f0f\uff0c\u4e0e\u5217\u8868\u751f\u6210\u5f0f\u7684\u8bed\u6cd5\u683c\u5f0f\u76f8\u540c\uff0c\u53ea\u9700\u8981\u5c06[]\u6362\u6210()\uff0c\u5373\uff1a<\/p>\n
<\/div><\/p>\n\uff08expression for item in iterable if condition\uff09<\/code><\/pre>\n\u5bf9\u6bd4\u5217\u8868\u751f\u6210\u5f0f\u8fd4\u56de\u7684\u662f\u4e00\u4e2a\u5217\u8868\uff0c\u751f\u6210\u5668\u8868\u8fbe\u5f0f\u8fd4\u56de\u7684\u662f\u4e00\u4e2a\u751f\u6210\u5668\u5bf9\u8c61<\/p>\n
>>> [x*x for x in range(3)]\n[0, 1, 4]\n>>> g=(x*x for x in range(3))\n>>> g\n<generator object <genexpr> at 0x101be0ba0><\/code><\/pre>\n\u5bf9\u6bd4\u5217\u8868\u751f\u6210\u5f0f\uff0c\u751f\u6210\u5668\u8868\u8fbe\u5f0f\u7684\u4f18\u70b9\u81ea\u7136\u662f\u8282\u7701\u5185\u5b58\uff08\u4e00\u6b21\u53ea\u4ea7\u751f\u4e00\u4e2a\u503c\u5728\u5185\u5b58\u4e2d\uff09<\/p>\n
>>> next(g)\n0\n>>> next(g)\n1\n>>> next(g)\n4\n>>> next(g) #\u629b\u51fa\u5f02\u5e38StopIteration<\/code><\/pre>\n\u5982\u679c\u6211\u4eec\u8981\u8bfb\u53d6\u4e00\u4e2a\u5927\u6587\u4ef6\u7684\u5b57\u8282\u6570\uff0c\u5e94\u8be5\u57fa\u4e8e\u751f\u6210\u5668\u8868\u8fbe\u5f0f\u7684\u65b9\u5f0f\u5b8c\u6210<\/p>\n
with open('db.txt','rb') as f:\n nums=(len(line) for line in f)\n total_size=sum(nums) # \u4f9d\u6b21\u6267\u884cnext(nums)\uff0c\u7136\u540e\u7d2f\u52a0\u5230\u4e00\u8d77\u5f97\u5230\u7ed3\u679c=<\/code><\/pre>\n<\/div><\/p>\n","protected":false},"excerpt":{"rendered":"\u4e00 \u751f\u6210\u5668\u4e0eyield \u82e5\u51fd\u6570\u4f53\u5305\u542byield\u5173\u952e\u5b57\uff0c\u518d\u8c03\u7528\u51fd\u6570\uff0c\u5e76\u4e0d\u4f1a\u6267\u884c\u51fd\u6570\u4f53\u4ee3\u7801\uff0c\u5f97\u5230\u7684\u8fd4\u56de\u503c\u5373\u751f\u6210\u5668\u5bf9 […]<\/p>\n","protected":false},"author":3,"featured_media":6697,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":[],"categories":[3,281,326],"tags":[],"_links":{"self":[{"href":"https:\/\/egonlin.com\/index.php?rest_route=\/wp\/v2\/posts\/4114"}],"collection":[{"href":"https:\/\/egonlin.com\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/egonlin.com\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/egonlin.com\/index.php?rest_route=\/wp\/v2\/users\/3"}],"replies":[{"embeddable":true,"href":"https:\/\/egonlin.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=4114"}],"version-history":[{"count":0,"href":"https:\/\/egonlin.com\/index.php?rest_route=\/wp\/v2\/posts\/4114\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/egonlin.com\/index.php?rest_route=\/wp\/v2\/media\/6697"}],"wp:attachment":[{"href":"https:\/\/egonlin.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=4114"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/egonlin.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=4114"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/egonlin.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=4114"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
![\"\u6076\u641e\u56fe50\"](\"\u914d\u56fe\/\u6076\u641e\u56fe\/\u6076\u641e\u56fe50.jpg\")
<\/div><\/p>\n![\"\"](\"https:\/\/egonlin.com\/wp-content\/uploads\/2022\/03\/\u6076\u641e\u56fe51.jpeg\")
<\/div><\/p>\n![\"\"](\"https:\/\/egonlin.com\/wp-content\/uploads\/2022\/03\/\u6076\u641e\u56fe52.jpg\")
<\/div><\/p>\n![\"\"](\"https:\/\/egonlin.com\/wp-content\/uploads\/2022\/03\/\u6076\u641e\u56fe53.jpg\")
<\/div><\/p>\n![\"\"](\"https:\/\/egonlin.com\/wp-content\/uploads\/2022\/03\/\u6076\u641e\u56fe54.jpg\")
<\/div><\/p>\n![\"\"](\"https:\/\/egonlin.com\/wp-content\/uploads\/2022\/03\/\u6076\u641e\u56fe55.jpg\")
<\/div><\/p>\n![\"\"](\"https:\/\/egonlin.com\/wp-content\/uploads\/2022\/03\/\u6076\u641e\u56fe56.jpg\")
<\/div><\/p>\n![\"\"](\"https:\/\/egonlin.com\/wp-content\/uploads\/2022\/03\/01-36-\u8001\u6bcd\u9e21.jpg\")
<\/div><\/p>\n![\"\"](\"https:\/\/egonlin.com\/wp-content\/uploads\/2022\/03\/\u6076\u641e\u56fe57.png\")
<\/div><\/p>\n","protected":false},"excerpt":{"rendered":"