用条件连接两个数据框（坐标和年份对应）

Question

我在尝试在特定条件下连接两个数据帧时遇到问题。 我看了不同的帖子，但没有找到对我有帮助的解决方案。

这是我的数据：

Dataframe 1 :

"year"     "var"          "x"                 "y"               "info"
"1992","mean_ndvi","4878686.57157449","5393968.15997648","0.386875003576279"
"1992","mean_ndvi","4896433.83572102","5398120.2484886","0.373374998569489"
"1992","mean_ndvi","4900572.93504345","5370687.20427196","0.394125014543533"
"1992","mean_ndvi","4902934.77310431","5361773.82267221","0.271333336830139"
"1992","mean_ndvi","4763325.11415408","5286260.42907455","0.341958343982697"
"1992","mean_ndvi","4659782.7218849","5251960.76092113","0.407333344221115"
"1992","mean_ndvi","4672416.53746615","5253639.4841048","0.443416655063629"
"1992","mean_ndvi","4688194.71187035","5255824.40292703","0.334916681051254"
"1992","mean_ndvi","4697653.82879809","5257181.46577816","0.367166668176651"

Dataframe 2 :

"year"         "x"             "y"             "species"
 "2014" "4001758.3924046" "3138415.9463486"     "Sus scrofa"
 "2016" "3990684.89200331" "3088575.79671371" "Capreolus capreolus"
 "2014" "4002641.44272945" "3078682.12799716" "Capreolus capreolus"
 "2014" "3946723.09681777" "3153792.59524072" "Capreolus capreolus"
 "2014" "3975356.46700669" "2974349.6604129" "Cervus elaphus"
 "2014" "4001283.9265329" "3137527.57584417" "Capreolus capreolus"
 "2014" "3946723.09681777" "3153792.59524072" "Capreolus capreolus"
 "2014" "3946723.09681777" "3153792.59524072" "Capreolus capreolus"
 "2017" "4000195.01511827" "3103181.07855945" "Capreolus capreolus"

第一个dataframe 包含的data 比第二个多。 我想做的是： concatenate 两个 dataframes 并仅保留第一个 dataframe 中出现的第二个 dataframe 中的 row。

我尝试了不同的方法：select and filter, merge, cbind, "by hand" with for loops，但我无法获得任何有效的方法。

我也花了很多时间在网上寻找解决方案，但是，或者我太笨了，看不出如何使用一种解决方案来解决我的问题，或者没有人有同样的问题，我不知道，或者我没有做足够的研究。

如果您对我如何做到这一点有任何线索，我知道这很简单。

Datafrale 1 :

"1992","mean_ndvi","4688194.71187035","5255824.40292703","0.334916681051254"
"1992","mean_ndvi","4697653.82879809","5257181.46577816","0.367166668176651"
"1992","mean_ndvi","4657938.8843526","5242452.09422199","0.43491667509079"
"1992","mean_ndvi","4661111.26475011","5242863.65256642","0.523041665554047"
"1992","mean_ndvi","4692800.91855509","5247191.53424558","0.405791670084"

Dataframe 2 :

"2014" "4001758.3924046" "3138415.9463486" "Sus scrofa"
"2016" "3990684.89200331" "3088575.79671371" "Capreolus capreolus"
"1992" "4657938.8843526" "5242452.09422199" "Capreolus capreolus"
"2017" "4000167.53545378" "3103446.42513062" "Sus scrofa"
"1992" "4688194.71187035" "5255824.40292703 "Capreolus capreolus"

Result : 

"1992" "4657938.8843526" "5242452.09422199" "Capreolus capreolus""0.43491667509079"
"1992" "4688194.71187035" "5255824.40292703 "Capreolus capreolus" "0.334916681051254"

这是 dput 的结果（前 10 行）：

First dataframe (with a lot of data)
structure(list(x = c(4878686.57157449, 4896433.83572102, 4900572.93504345, 
4902934.77310431, 4763325.11415408, 4659782.7218849, 4672416.53746615, 
4688194.71187035, 4697653.82879809, 4657938.8843526), y =     c(5393968.15997648, 
5398120.2484886, 5370687.20427196, 5361773.82267221, 5286260.42907455, 
5251960.76092113, 5253639.4841048, 5255824.40292703, 5257181.46577816, 
5242452.09422199), year = c(1993L, 1993L, 1993L, 1993L, 1993L, 
1993L, 1993L, 1993L, 1993L, 1993L), info = c(0.396166652441025, 
0.373374998569489, 0.394125014543533, 0.28979167342186, 0.344375014305115, 
0.414458334445953, 0.416541665792465, 0.342583328485489, 0.378208339214325, 
0.440750002861023)), .Names = c("x", "y", "year", "info"), row.names = c(NA, 
10L), class = "data.frame")

它返回另一个数据帧的整个数据帧，我不明白为什么，但我不能把它说成没有任何意义的结果

Answer 1

试试这个：

# Get fancy data
set.seed(666)

df1 <- iris[sample(x = 1:10, size = 6, replace = FALSE),]
df2 <- iris[sample(x = 1:10, size = 6, replace = FALSE),]

# Get common rows
index <- match(apply(df1, 1, paste, collapse = "-"), 
               apply(df2, 1, paste, collapse = "-"))
index <- index[!is.na(index)]

df3 <- df2[index,]

如您所见，df3 将是一个只有公共行的 data.frame。