Scrapy, why can both return and yield operate?

has been distributed recently, but both yield and return can return data when crawling. Why?
ask for advice

tags.append (tag ["name"]) 

item["tags"] = ",".join(tags)
item["fullName"] = companyData["fullName"]
item["scale"] = companyData["scale"]
asTs, asEncryptedTs = execjs.compile(self.js_read).call("p")
kw_url = "https://rong.36kr.com/n/api/search/company?asEncryptedTs={}&asTs={}&kw={}&sortField=MATCH_RATE".format(
    asEncryptedTs, asTs, item["name"])

retunr scrapy.Request(
    url=kw_url,
    callback=self.get_kw_info,
    dont_filter=True,
    meta={"id": response.meta["id"], "item": item},
)

def get_kw_info (self, response): 

item = response.meta["item"]
pageData = json.loads(response.text)["data"]["pageData"]["data"]
industryStr = pageData[0]["industryStr"]
item["industryStr"] = industryStr
asTs, asEncryptedTs = execjs.compile(self.js_read).call("p")
finance_link = "https://rong.36kr.com/n/api/company/{}/finance?asEncryptedTs={}&asTs={}".format(
    response.meta["id"], asEncryptedTs, asTs)
retun scrapy.Request(
    url=finance_link,
    callback=self.get_finance_info,
    dont_filter=True,
    meta={"id": response.meta["id"], "item": item})

does this code always return data from both yield and return? Why is that?

Python
Feb.04,2022

this question is actually the difference between yield and return , return need not say much, certainly understand. So the question becomes what yield is.

you may need to understand what a generator is before entering the text, and you need to understand what iteration is before a generator.

< H1 > iteration < / H1 >

if a list, it is an iterable object, called Iterable in Python. 

In [15]: def foo():
    ...:     _list = range(4)
    ...:     print('run in func')
    ...:     for i in _list:
    ...:         print('run in loop')
    ...:         yield i
    ...:
    ...:

In [16]: gen = foo()

In [17]: for i in gen:
    ...:     print(i)
    ...:
    ...:
run in func
run in loop
0
run in loop
1
run in loop
2
run in loop
3

so you should understand the difference between return and yield in Scrapy ~

Previous: Ask the question about the implementation of the front-end template engine?

Next: With the help of a js plug-in, the main function is to draw tables with large amounts of data and to perform formula calculations.

css mysql arrays josn react html typescript webpack npm sass R objective-c .net sql-server jquery python-3.x angularjs django angular excel regex iphone ajax linux xml pandas vba spring database wordpress string wpf xcode windows bash postgresql oracle multithreading eclipse list firebase algorithm macos forms image scala visual-studio azure bootstrap spring-boot react-native python-2.7 docker performance function winforms matlab powershell apache dataframe api sqlite numpy rest shell selenium flutter dart maven loops qt swing android-studio csv express file class tensorflow sorting codeigniter perl
MySQL Query : SELECT * FROM `codeshelper`.`v9_news` WHERE status=99 AND catid='6' ORDER BY rand() LIMIT 5
MySQL Error : Disk full (/tmp/#sql-temptable-64f5-1e47630-44c2f.MAI); waiting for someone to free some space... (errno: 28 "No space left on device")
MySQL Errno : 1021
Message : Disk full (/tmp/#sql-temptable-64f5-1e47630-44c2f.MAI); waiting for someone to free some space... (errno: 28 "No space left on device")
Need Help?