我正在尝试从NOAA拆开天气警报的包装。
https://api.weather.gov/alerts
library(jsonlite)
#API
string = "https://api.weather.gov/alerts"
#import json and flatten
json_data <- fromJSON(string,flatten=TRUE)
#get names
names(json_data)
[1] "@context" "type" "features" "title" "updated"
#extract the features
final_data <- as.data.table(json_data$features)
这将产生一个表格,我可以从中获取有关每个警报的详细信息。但是,一些结果会进一步嵌套。例如:
head(final_data$properties.geocode.UGC,1)
[[1]]
[1] "AMZ732" "AMZ741" "AMZ715" "AMZ725" "AMZ712" "AMZ710"
我想打开这些包装并旋转桌子,所以每一行应该是:
warning | properties.geocode.UGC
storm | AMZ732
storm | AMZ741
storm | AMZ715
storm | AMZ725
storm | AMZ712
storm | AMZ710
我该怎么做?它会涉及取消列出该列吗?
答案 0 :(得分:0)
听起来您不需要 GeoJSON,所以我们将使用JSON-LD端点:
httr::GET(
url = "https://api.weather.gov/alerts",
httr::accept("application/ld+json")
) -> res
x <- jsonlite::fromJSON(rawToChar(httr::content(res)))[["@graph"]]
x <- cbind.data.frame(x, x$geocode, x$parameters)
x$geocode <- NULL
x$parameters <- NULL
colnames(x) <- make.names(colnames(x), unique=TRUE)
x <- tidyr::unnest(x, UGC)
dplyr::data_frame(
id = x$id,
event = x$event,
ugc = x$UGC
)
## # A tibble: 1,792 x 3
## id event ugc
## <chr> <chr> <chr>
## 1 NWS-IDP-PROD-3212197-2821047 Freeze Warning NMZ538
## 2 NWS-IDP-PROD-KEEPALIVE-22857 Test Message MDC031
## 3 NWS-IDP-PROD-3212196-2821046 Special Marine Warning GMZ650
## 4 NWS-IDP-PROD-3212196-2821046 Special Marine Warning GMZ670
## 5 NWS-IDP-PROD-3212195-2821045 Wind Advisory UTZ019
## 6 NWS-IDP-PROD-3212194-2821044 Red Flag Warning CAZ211
## 7 NWS-IDP-PROD-3212194-2821044 Red Flag Warning CAZ204
## 8 NWS-IDP-PROD-3212194-2821044 Red Flag Warning CAZ283
## 9 NWS-IDP-PROD-3212194-2821044 Red Flag Warning CAZ277
## 10 NWS-IDP-PROD-3212194-2821044 Red Flag Warning CAZ203
## # ... with 1,782 more rows