python ros怎么写回调函数处理返回值 ros subscriber回调机制,实验程序:talker.cc #include<std_msgs/Int32.h>#include<ros/ros.h>intmain(intargc,char**argv){ros::init(argc,argv,"talker");ros::NodeHandlenh;std_msgs::Int32dat
extract() print title, link, desc 如果不用回调函数,下面这样写对吗? article = Request(url="http://www.example.com/article-1.html") # 下面这样写对吗? title = article.xpath('a/text()').extract() link = article.xpath('a/@href').extract() desc = article.xpath('text()').extract()...
line 1, in <module>File "/u01/bigdata/anaconda3/lib/python3.9/site-packages/psycopg2-2.9-py3.9-linux-x86_64.egg/psycopg2/init.py",line 51, in <module>from psycopg2._psycopg import ( # noqaImportErro...