R-按组查找公共元素

我正在使用以下数据集

library(data.table)
dat <- fread("https://www.dropbox.com/s/kj66h9shv6zge91/mydat.csv?dl=1")

对于每个

变量id

，我试图找到

源id

中同时存在于

实验id

所有元素中的元素列表（例如，“历史”、“ssp126”、“ssp245”、“ssp370”、“ssp585”）

有什么办法去那里吗？看起来是一个简单的问题，但我在上找不到合适的答案，因此无法使用字符而不是数字值。

也许这会有帮助：

by(dat, dat$variable_id, function(x) 
        Reduce(intersect, split(x$source_id, x$experiment_id)))

#dat$variable_id: pr
# [1] "BCC-CSM2-MR" "MRI-ESM2-0"  "CESM2-WACCM" "INM-CM5-0"  "INM-CM4-8"    
# [6] "MPI-ESM1-2-HR" "CMCC-CM2-SR5"  "NorESM2-MM"  "EC-Earth3"  "EC-Earth3-Veg"
#[11] "GFDL-ESM4"    
#-------------------------------------------------------------------------- 
#dat$variable_id: tas
# [1] "BCC-CSM2-MR"   "MRI-ESM2-0"    "CESM2-WACCM"   "AWI-CM-1-1-MR" "INM-CM4-8"
# [6] "INM-CM5-0"     "MPI-ESM1-2-HR" "CMCC-CM2-SR5"  "NorESM2-MM"    "EC-Earth3"
#[11] "EC-Earth3-Veg" "GFDL-ESM4"    
#-------------------------------------------------------------------------- 
#dat$variable_id: tasmax
# [1] "BCC-CSM2-MR"   "MRI-ESM2-0"    "AWI-CM-1-1-MR" "INM-CM4-8"     "INM-CM5-0"
# [6] "MPI-ESM1-2-HR" "NorESM2-MM"    "EC-Earth3"     "EC-Earth3-Veg" "GFDL-ESM4"
#-------------------------------------------------------------------------- 
#dat$variable_id: tasmin
# [1] "BCC-CSM2-MR"   "MRI-ESM2-0"    "AWI-CM-1-1-MR" "INM-CM4-8"     "INM-CM5-0"
# [6] "MPI-ESM1-2-HR" "NorESM2-MM"    "EC-Earth3"     "EC-Earth3-Veg" "GFDL-ESM4"

对于每个

变量_id

这将返回所有

实验_id

中存在的公共

源_id

---

如果您想为每个

变量\u id

和每个

实验\u id

Reduce(intersect, split(dat$source_id, list(dat$variable_id, dat$experiment_id)))

#[1] "BCC-CSM2-MR"   "MRI-ESM2-0"    "INM-CM5-0"     "INM-CM4-8"    
#[5] "MPI-ESM1-2-HR" "NorESM2-MM"    "EC-Earth3"     "EC-Earth3-Veg"
#[9] "GFDL-ESM4"    

---

太棒了，这正是我们想要的！

Reduce(intersect, split(dat$source_id, list(dat$variable_id, dat$experiment_id)))

#[1] "BCC-CSM2-MR"   "MRI-ESM2-0"    "INM-CM5-0"     "INM-CM4-8"    
#[5] "MPI-ESM1-2-HR" "NorESM2-MM"    "EC-Earth3"     "EC-Earth3-Veg"
#[9] "GFDL-ESM4"