无法使用Google API

Question

我使用谷歌地图API来获取geoocode财富500强企业的坐标但是，当我运行它时，它仍然会定期显示OVER_QUERY_LIMIT因此我的地理编码列表不完整。所以我有两个问题：

1. 如何获取所有地理编码（我的代码错了）？
2. 如何在R环境中编辑我的API密钥＆amp;在我的代码中找到它？

获得Fortune500名单：

    library(XML)
    library(RCurl)
    fortune500_url <- getURL("https://www.geolounge.com/fortune-500-list-by-
    state-for-2015/",.opts = list(ssl.verifypeer = FALSE) ) 
    fortune500 = readHTMLTable(fortune500_url, header = TRUE, which = 1)
    colnames(fortune500) <- tolower(colnames(fortune500))
    fortune500 <- 
    subset(fortune500,select=c("company","streetadd","place","state","zip"))
    write.csv(fortune500, "fortune500.csv")

无法获得以下所有Fortune500公司的坐标：

    # Add API key to renviron file
    usethis::edit_r_environ() # how do we assign API key to a variable?

    # Install Developer version of ggmap to use maps API Key

    devtools::install_github("dkahle/ggmap")
    library(ggmap)

    register_google(key = Sys.getenv("MY_API_KEY")) # how to source my key from R environment ?

    fortune500$address <- paste(fortune500$streetadd, fortune500$place, 
    fortune500$state, fortune500$zip)

    geocodes <- geocode(fortune500$address, output = "latlon" , source = 
    "google")    # can't get all coordinates

感谢您的帮助。