R保存子集以列出索引

Question

目前，我正在这样做。它从聚合中对数据进行子集化。运行部件aggregate[which(aggregate$resolution == keys[i]), ]为我提供了我想要的聚合数据集的一部分。但是，当我尝试在for循环中执行此操作时，它会给我一堆关键字符串。

为什么会这样？

如何将子集放入列表中？

keys <- c()
keys[1] <- "2016_01_12_ban_on_booby-trapped_aid.tsv"              
keys[2] <- "2014_11_20_anti-counterfeiting_pact.tsv"              
keys[3] <- "2015_08_06_access_to_humanitarian_aid.tsv"            
keys[4] <- "2017_03_22_world_assembly_central_library_compact.tsv"
keys[5] <- "2017_08_31_national_sovereignty_act.tsv"              
keys[6] <- "2015_10_21_repeal_renewable_research_commitment.tsv"  
keys[7] <- "2017_07_29_limitations_on_banishment.tsv"             
keys[8] <- "2016_10_04_nuclear_weapons_accord.tsv"                
keys[9] <- "2017_03_07_international_patent_agreement.tsv"        
keys[10] <- "2016_04_30_repeal_law_enforcement_education.tsv"

subsets <- list()
for (i in 1:length(keys)) {
  subsets[i] = aggregate[which(aggregate$resolution == keys[i]), ]
}

Answer 1

解决了问题。

keys <- unique(aggregate$resolution)
subsets = list()
for (i in 1:length(keys)) {
  subsets[[i]] = as.data.frame(main_data_set[which(main_data_set$resolution == keys[i]), ])
}