我在从R中的数据框（exhibitionPlannings_1）中提取数据时遇到问题。
数据框如下所示：
> str(exhibitionPlannings_1)
'data.frame': 3 obs. of 4 variables:
$ date : chr "23.08.2018" "24.08.2018" "27.08.2018"
$ exhibitionLocations:List of 3
..$ :'data.frame': 2 obs. of 17 variables:
.. ..$ id : chr "ind-8cf04a9734132302f96da8e113e80ce5-0" "5"
.. ..$ title : chr "title1" "title2"
.. ..$ street : chr "street1" "street2"
.. ..$ $$hashKey : chr "object:57" "object:287"
.. ..$ exhibitorID :List of 2
.. .. ..$ : list()
.. .. ..$ : list()
.. ..$ zip : chr "" "32584"
.. ..$ city : chr "" "city2"
.. ..$ latitude : chr "" "12.345"
.. ..$ exhibitors :List of 2
.. .. ..$ : list()
.. .. ..$ : list()
.. ..$ distance2Neighbour : chr "123 km" ""
.. ..$ duration2Neighbour : chr "0 Stunden, 0 Minuten" ""
.. ..$ forum : logi NA TRUE
.. ..$ longitude : num NA 1.23
.. ..$ class : chr NA ""
.. ..$ distance2LastLocationInPlanning : chr NA "00 km"
.. ..$ distanceValue2LastLocationInPlanning: int NA 123456
.. ..$ duration2LastLocationInPlanning : chr NA "0 Stunden, 0 Minuten"
..$ :'data.frame': 1 obs. of 17 variables:
.. ..$ id : int 3
.. ..$ forum : logi FALSE
.. ..$ exhibitorID :List of 1
.. .. ..$ : list()
.. ..$ title : chr "title3"
.. ..$ street : chr "street3"
.. ..$ zip : chr "123456"
.. ..$ city : chr "city3"
.. ..$ latitude : num 12.3
.. ..$ longitude : num 1.23
.. ..$ class : chr ""
.. ..$ exhibitors :List of 1
.. .. ..$ : list()
.. ..$ $$hashKey : chr "object:310"
.. ..$ distance2LastLocationInPlanning : chr "0 km"
.. ..$ distanceValue2LastLocationInPlanning: int 123456
.. ..$ duration2LastLocationInPlanning : chr "0 Stunden, 0 Minuten"
.. ..$ distance2Neighbour : chr ""
.. ..$ duration2Neighbour : chr ""
..$ :'data.frame': 2 obs. of 17 variables:
.. ..$ id : chr "ind-4dbe13088312d7841a318997b1426dd0-3" "5"
.. ..$ title : chr "title4" "title5"
.. ..$ street : chr "street4" "street5"
.. ..$ $$hashKey : chr "object:60" "object:287"
.. ..$ exhibitorID :List of 2
.. .. ..$ : int
.. .. ..$ : int 1 10 25 37 38 56 74
.. ..$ zip : chr "" "123456"
.. ..$ city : chr "" "city5"
.. ..$ latitude : chr "" "12.345"
.. ..$ exhibitors :List of 2
.. .. ..$ :'data.frame': 0 obs. of 0 variables
.. .. ..$ :'data.frame': 1 obs. of 8 variables:
.. .. .. ..$ id : int 1
.. .. .. ..$ title : chr "ABC"
.. .. .. ..$ contentUri : chr "uri.com"
.. .. .. ..$ locationName:List of 1
.. .. .. .. ..$ : chr "location Name"
.. .. .. ..$ locationID :List of 1
.. .. .. .. ..$ : int 5
.. .. .. ..$ image : chr "www.image.com"
.. .. .. ..$ class : chr "favorite"
.. .. .. ..$ $$hashKey : chr "object:65"
.. ..$ distance2LastLocationInPlanning : chr "12,3 km" "456 km"
.. ..$ distanceValue2LastLocationInPlanning: int 12345 6789
.. ..$ duration2LastLocationInPlanning : chr "00 Minuten" "0 Stunden, 00 Minuten"
.. ..$ distance2Neighbour : chr "0 km" ""
.. ..$ duration2Neighbour : chr "0 Stunden, 00 Minuten" ""
.. ..$ forum : logi NA TRUE
.. ..$ longitude : num NA 1.23
.. ..$ class : chr NA ""
$ $$hashKey : chr "object:298" "object:438" "object:562"
$ googleStaticMap : chr "https://maps.googleapis.com/maps/api/staticmap?123"| __truncated__
您可以看到“日期”有3个日期，“ exhibitionLocations”是3个元素的列表，其中每个元素都是一个数据框。
我想向每个这些数据框添加一个新列。此列应包含相应的日期。
结果应如下所示：
date | id | title | street
23.08.2018 | "ind-8cf04a9734132302f96da8e113e80ce5-0" | "title1" | "street1"
23.08.2018 | "5" | "title2" | "street2"
24.08.2018 | 3 | "title3" | "street3"
27.08.2018 | "ind-4dbe13088312d7841a318997b1426dd0-3" | "title4" | "street4"
27.08.2018 | "5" | "title5" | "street5"
如果您可以通过map（）建议解决方案，我会很高兴。
非常感谢！
答案 0 :(得分：0)
您可以使用mapply将一个函数应用于两个参数（字符向量和data.frame列表），然后使用do.call rb mapply的结果：
# data.frame simulation
df <- structure(list(date = c("23.08.2018", "24.08.2018", "27.08.2018"
), dfs = structure(list(structure(list(id = structure(2:1, .Label = c("5",
"ind-8cf04a9734132302f96da8e113e80ce5-0"), class = "factor"),
title = structure(1:2, .Label = c("title1", "title2"), class = "factor"),
street = structure(1:2, .Label = c("street1", "street2"), class = "factor")), class = "data.frame", row.names = c(NA,
-2L)), structure(list(id = structure(1L, .Label = "3", class = "factor"),
title = structure(1L, .Label = "title3", class = "factor"),
street = structure(1L, .Label = "street3", class = "factor")), class = "data.frame", row.names = c(NA,
-1L)), structure(list(id = structure(2:1, .Label = c("5", "ind-4dbe13088312d7841a318997b1426dd0-3"
), class = "factor"), title = structure(1:2, .Label = c("title4",
"title5"), class = "factor"), street = structure(1:2, .Label = c("street4",
"street5"), class = "factor")), class = "data.frame", row.names = c(NA,
-2L))), class = "AsIs")), class = "data.frame", row.names = c(NA,
-3L))
# extract and concatenate the data
dfs <- mapply(function(x, y) {
y$date <- x
y
} , df$date, df$dfs, SIMPLIFY = FALSE)
do.call(rbind, dfs)
输出：
id title street date
23.08.2018.1 ind-8cf04a9734132302f96da8e113e80ce5-0 title1 street1 23.08.2018
23.08.2018.2 5 title2 street2 23.08.2018
24.08.2018 3 title3 street3 24.08.2018
27.08.2018.1 ind-4dbe13088312d7841a318997b1426dd0-3 title4 street4 27.08.2018
27.08.2018.2 5 title5 street5 27.08.2018