R中的复杂非等式合并 [英] Complexe non-equi merge in R
问题描述
我正在尝试在两个表之间进行复杂的非 equi 连接.我从上一次 userR2016 的演示中得到启发(https://channel9.msdn.com/events/useR-international-R-User-conference/user2016/Efficient-in-memory-non-equi-joins-using-datatable) 这让我相信这将是 data.table 的合适任务.我的表 1 看起来像:
I'm trying to do a complexe non-equi join between two tables. I got inspired by a presentation in the last useR2016 (https://channel9.msdn.com/events/useR-international-R-User-conference/useR2016/Efficient-in-memory-non-equi-joins-using-datatable) which made me believe it would be a suitable task for data.table. My table 1 looks like:
library(data.table)
sp <- c("SAB","SAB","SAB","SAB","EPN","EPN","BOP","BOP","BOP","BOP","BOP","PET","PET","PET")
dbh <- c(10,12,16,22,12,16,10,12,14,20,26,12,16,18)
dt1 <- data.table(sp,dbh)
dt1
sp dbh
1: SAB 10
2: SAB 12
3: SAB 16
4: SAB 22
5: EPN 12
6: EPN 16
7: BOP 10
8: BOP 12
9: BOP 14
10: BOP 20
11: BOP 26
12: PET 12
13: PET 16
14: PET 18
这是一个带有 dbh 的树列表.我的第二个表(如下)给出了一个通用表,它为每个树种提供了一个 dbh 范围来对大小等级或树进行分类:
It's a list of trees with their dbh. My second table (below) gives a generic table that gives for each tree species a range of dbh to classify the size class or the tree:
gr_sp <- c("RES","RES","RES","RES","RES","RES", "DEC", "DEC", "DEC", "DEC", "DEC", "DEC")
sp <- c("SAB","SAB", "SAB", "EPN", "EPN", "EPN", "BOP", "BOP", "BOP", "PET", "PET", "PET")
dbh_min <- c(10, 16, 22, 10, 14, 20, 10, 18, 24, 10, 20, 26)
dbh_max <- c(14, 20, 30, 12, 18, 30, 16, 22, 30, 18, 24, 30)
dhb_clas <- c("s", "m", "l", "s", "m", "l", "s", "m", "l", "s", "m", "l")
dt2 <- data.table(gr_sp, sp, dbh_min, dbh_max, dhb_clas)
dt2
gr_sp sp dbh_min dbh_max dhb_clas
1: RES SAB 10 14 s
2: RES SAB 16 20 m
3: RES SAB 22 30 l
4: RES EPN 10 12 s
5: RES EPN 14 18 m
6: RES EPN 20 30 l
7: DEC BOP 10 16 s
8: DEC BOP 18 22 m
9: DEC BOP 24 30 l
10: DEC PET 10 18 s
11: DEC PET 20 24 m
12: DEC PET 26 30 l
我希望我的最终表是按物种(sp"字段)和DBH_MIN"和DBH_MAX"规定的 dhb 范围内的两个表的连接.这将使我的桌子看起来像:
I want my final table to be the join of the two tables by species ("sp" field) and within the range of dhb stated by "DBH_MIN" and "DBH_MAX". That would make my table looks like:
data.table(dt1, gr_sp = c("RES","RES","RES","RES","RES","RES","DEC","DEC","DEC","DEC","DEC","DEC","DEC","DEC"), dhb_clas = c("s","s","m","l","s","m","s","s","s","m","l","s","s","s"))
sp dbh gr_sp dhb_clas
1: SAB 10 RES s
2: SAB 12 RES s
3: SAB 16 RES m
4: SAB 22 RES l
5: EPN 12 RES s
6: EPN 16 RES m
7: BOP 10 DEC s
8: BOP 12 DEC s
9: BOP 14 DEC s
10: BOP 20 DEC m
11: BOP 26 DEC l
12: PET 12 DEC s
13: PET 16 DEC s
14: PET 18 DEC s
我尝试过类似的方法:
dt1[dt2, on=.(sp=sp, dbh>=dbh_min, dbh<=dbh_max)]
这给出了太多的行...
which gives too many rows...
感谢您的帮助
推荐答案
所以我非常接近.我有 2 个问题,首先是 data.table 包的安装错误(数据表错误找不到函数.")导致了一个模糊的错误.
So I was very close. I had 2 problems, first a bad installation of the data.table package (Data table error could not find function ".") caused an obscure error.
解决了这个问题后,我走近发现:
After having fixed that, I got closer an found that :
dt1[dt2, on=.(sp=sp, dbh>=dbh_min, dbh<=dbh_max), nomatch=0]
用糟糕的 dbh 列给了我想要的东西.使用以下命令反转命令:
gave me what I wanted with a bad dbh column. Inverting the command with:
dt2[dt1, on=.(sp=sp, dbh_min<=dbh, dbh_max>=dbh)]
修复了只有一个无用的额外列的问题.
fixed the problem with only one useless extra column.
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