library(rvest) myurl <- "http://www.boohee.com/food/group/" food_cal <- ...

一. Workspace and Files 1. getwd()当前的工作空间 2. ls()工作空间下所有对象 3. list.files(...

1. read_html(url, encoding = "") 下载html页面, url为网址，encoding为网址编码 2. html_...