R中的非复杂合并 [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等额联接。我受到上次useR2016( https://channel9.msdn.com/events/useR-international-R-User-conference/useR2016/Efficient-in-memory-non-equi-joins-using- datatable ),这使我相信这对于data.table是合适的任务。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
这是树木及其dbh的列表。我的第二张表(下面)提供了一个通用表,该表为每种树种类提供了一定范围的dbh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
我希望我的最终表成为按物种划分的两个表的联接( sp字段)并在 DBH_MIN和 DBH_MAX指定的dhb范围内。那会使我的表看起来像这样:
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
我尝试过以下操作:
dt1[dt2, on=.(sp=sp, dbh>=dbh_min, dbh<=dbh_max)]
该行太多了...
感谢您的帮助
所以我很亲近。我有2个问题,首先是data.table软件包的安装不正确(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.
在修复该问题之后,我更接近了一个发现:
After having fixed that, I got closer an found that :
dt1[dt2, on=.(sp=sp, dbh>=dbh_min, dbh<=dbh_max), nomatch=0]
用不好的dbh列为我提供了我想要的东西。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)]
仅用了一个无用的额外列即可解决此问题。
fixed the problem with only one useless extra column.
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