r语言 - 在使用bind.pages时，从JSON中填充api列表的空白参数

Question

在"search"部分使用foursquare API提取给定经度和纬度点的特定地点的数据。在拉的过程中，有一个"类别"的部分给我带来了麻烦。我一直在使用我之前问过的一个问题的建议:在R

中嵌套数据帧的列表

然而，这是使用FS的"探索"API，它工作得很好。现在我正在使用"搜索"API，一些后期长点正在拉入没有类别的嵌套数据框架:

                        id               name          pluralName
1 4bf58dd8d48988d1c1941735 Mexican Restaurant Mexican Restaurants
  shortName                                          icon.prefix
1   Mexican https://ss3.4sqi.net/img/categories_v2/food/mexican_
  icon.suffix primary
1        .png    TRUE
[[14]]
**data frame with 0 columns and 0 rows**
[[15]]
                        id        name   pluralName   shortName
1 4bf58dd8d48988d11b951735 Flower Shop Flower Shops Flower Shop
                                               icon.prefix icon.suffix
1 https://ss3.4sqi.net/img/categories_v2/shops/flowershop_        .png
  primary
1    TRUE

我依赖于中国，因为id不兼容合并。我如何解释这些零，并将类别构建为"NA"，以便当我绑定时，我不会得到以下错误?从本质上讲，取消列表函数杀死了零数据帧，缩短了列表以绑定

Error in data.frame(..., check.names = FALSE) : 
  arguments imply differing number of rows: 30, 29

下面是我的代码:

foursquare<-function(x,y,z,r){
    w<-paste("https://api.foursquare.com/v2/venues/search?ll=",x,
             "&radius=",r,"&oauth_token=",y,"&v=",z,sep="")
    u<-getURL(w)
    test<-fromJSON(u)
    {locationid =""
      locationname=""
      location =""
      lat=""
      long=""
      categories = ""
      checkinscount = ""
      userscount = ""
      beenhere=""
      herenow=""}
    for(n in 1:length(test$response$venues)) {
      #extract
      locationid = test$response$venues$id
      locationname = test$response$venues$name
      location= test$response$venues$location$address
      lat = test$response$venues$location$lat
      long = test$response$venues$location$lng
      categories= test$response$venues$categories
      checkinscount = test$response$venues$stats$checkinsCount
      userscount = test$response$venues$stats$usersCount
      beenhere = test$response$venues$beenHere$unconfirmedCount
      herenow = test$response$venues$hereNow$count

      search_api = as.data.frame(cbind(locationid, locationname, location, lat, long,
                                       checkinscount,userscount, beenhere, herenow))
      print(categories)
      categories = jsonlite::rbind.pages(categories)
      categories = categories[, c("name")]
      print(categories)
      search_api = as.data.frame(cbind(search_api, categories))
    }
    #add columns
    search_api$pulled_date = Sys.time()
    search_api$x_query = paste(x)
    search_api$y_query = y
    search_api$type_api = 'search'
    search_api$radius = paste(r)
    #prep for writeout
    time = gsub("[[:punct:]]", "", Sys.time())
    filename <- paste(time,"search_api",".csv", sep="") 
    print(filename)
    write.csv(search_api, file = filename)
  }
  foursquare("40.7575425406984,-73.9295267264121","auth_tok","20161027", 1000)

Answer 1

categories是一个向量吗?你能把它装上NA吗?

if (length(categories) < 30) {categories <- c(categories, rep(NA, 30 - length(categories)))}