將Elastic（嵌套列表？）包的R輸出轉換爲data.frame或JSON

Question

我正在使用R和包'elastic'來查詢包含JSON格式的twitter數據的彈性搜索數據庫。查詢工作正常，我得到的輸出內容（出），如我所料。

class(out) 
[1] "list" 

進出$ $命中命中回報

> out$hits$hits 
[[1]] 
[[1]]$`_index` 
[1] "twitter_all_geo-2014-11-01" 

[[1]]$`_type` 
[1] "ctweet" 

[[1]]$`_id` 
[1] "ubicity-twitter-160f0964-6fc7-43ef-af2a-0e1b8c8184c7" 

[[1]]$`_version` 
[1] 1 

[[1]]$`_score` 
[1] 2.10757 

[[1]]$`_source` 
[[1]]$`_source`$id 
[1] "528330489049120770" 

[[1]]$`_source`$created_at 
[1] "2014-10-31T23:39:39+0000" 

[[1]]$`_source`$user 
[[1]]$`_source`$user$name 
[1] "afterlifetemis" 


[[1]]$`_source`$place 
[[1]]$`_source`$place$geo_point 
[[1]]$`_source`$place$geo_point[[1]] 
[1] 30.4529 

[[1]]$`_source`$place$geo_point[[2]] 
[1] 50.61104 


[[1]]$`_source`$place$city 
[1] "Ukraine" 

[[1]]$`_source`$place$country 
[1] "Ukraine" 

[[1]]$`_source`$place$country_code 
[1] "UA" 

[[1]]$`_source`$msg 
[[1]]$`_source`$msg$text 
[1] "u had one job artemis\none" 

[[1]]$`_source`$msg$lang 
[1] "EN" 

[[1]]$`_source`$msg$hash_tags 
list() 

[[2]] 
[[2]]$`_index` 
[1] "twitter_all_geo-2014-11-01" 

[[2]]$`_type` 
[1] "ctweet" 
... 
... 

基本上我想要的數據另存爲.csv文件，所以我進入

> write.csv(out$hits$hits,'out.csv') 
Error in data.frame(text = "u had one job artemis\none", lang = "EN", : arguments imply differing number of rows: 1, 0 

我認爲有必要將其轉換爲data.frame，因此我嘗試過：

> df <- ldply (out, data.frame) 

data.frame中的錯誤（text =「你有一個job artemis \ none」，lang =「EN」，： 參數意味着不同的行數：1,

（我嘗試了幾個其他的optimistc嘗試太喜歡這一個:)

> t(sapply(out$hits$hits, '[', 1:max(sapply(out$hits$hits, length)))) 
    _index      _type _id              _version _score _source 
[1,] "twitter_all_geo-2014-11-01" "ctweet" "ubicity-twitter-160f0964-6fc7-43ef-af2a-0e1b8c8184c7" 1  2.10757 List,5 
[2,] "twitter_all_geo-2014-11-01" "ctweet" "ubicity-twitter-ba071fff-cafb-4d3f-947d-13c934905c1b" 1  2.10757 List,5 
[3,] "twitter_all_geo-2014-11-01" "ctweet" "ubicity-twitter-dd64af32-4d59-4008-a3db-74471ad269d1" 1  2.10757 List,5 
[4,] "twitter_all_geo-2014-11-01" "ctweet" "ubicity-twitter-4ba0d3d0-642d-4f9f-aaf9-c55929c35dc4" 1  2.10757 List,5 
[5,] "twitter_all_geo-2014-11-01" "ctweet" "ubicity-twitter-d7b8cbbc-87b3-44b5-8c9c-91c7b62f1458" 1  2.10757 List,5 
[6,] "twitter_all_geo-2014-11-01" "ctweet" "ubicity-twitter-76353a7c-44c9-4863-a59d-adb16716ca18" 1  2.10757 List,5 
[7,] "twitter_all_geo-2014-11-01" "ctweet" "ubicity-twitter-2aec0798-9918-4b66-9b2a-ef5a4d1f3711" 1  2.10757 List,5 
[8,] "twitter_all_geo-2014-11-01" "ctweet" "ubicity-twitter-c9e7637d-358a-40ee-a06c-85af04c22191" 1  2.10757 List,5 
[9,] "twitter_all_geo-2014-11-01" "ctweet" "ubicity-twitter-8928c1ef-f46a-4682-99c4-4dbc55270b03" 1  2.10757 List,5 
[10,] "twitter_all_geo-2014-11-01" "ctweet" "ubicity-twitter-d6b19975-b310-46c4-af11-af56971b7c4b" 1  2.10757 List,5 

而且在開始的時候看起來很不錯，但實際的tweet消息不再在矩陣

我很樂觀，想，也許第一（後）將其轉換JSON（使用RJSON）

toJSON（out） toJSON中的錯誤（out）：無法轉義字符串。字符串不是utf8

最後，我有一個列表，無法保存，無法轉換爲JSON，data.frame或data.table（因爲它不是統一的）。有沒有人可以給我提示a）將其轉換爲JSON或如何將列表保存爲.csv文件或將其放入data.frame中？

非常感謝，我想我不理解它。

-Tobias

Answer 1

我覺得unlist()和matrix()可以做的工作。

一個例子轉換Search() -return out成數據幀：

# get the first 3 hits from elasticsearch store 
out <- Search(index="shakespeare", size=3) 

# (optional) verify that all hits expand to the same length 
# (should be true for data intended to be in a table format) 
stopifnot(
    sapply(
     out$hits$hits, 
     function(x) {!(length(unlist(x)) - length(unlist(out$hits$hits[[1]])))} 
    ) 
) 

# count number of columns, use unlist() to convert 
# nested lists to a vector, use the first hit as proxy 
nColumns <- length(unlist(out$hits$hits[[1]])) 

# fetch column names ... as above 
nNames <- names(unlist(out$hits$hits[[1]])) 

# unlist all hits and convert to matrix with ncol Columns, don't forget byrow=TRUE! 
df <- data.frame(matrix(unlist(out$hits$hits), ncol=nColumns, byrow=TRUE)) 

# setting the column names 
names(df) <- nNames 

# do whatever you want with df 
print(df) 

乾杯！

Answer 2

您可以在河使用「JQR」包如： -

datacsv<-jq(out,".hits.hits[] | @csv") 

將您的數據保存到CSV格式，並以「JQR」的幫助下，你可以用grep也你想要的領域。