使用原始行中的两个列值将一行熔化/拆分为两行,其余部分保持不变 [英] Melting/Splitting a row into two rows, using two column values in the original row, leaving the rest intact
本文介绍了使用原始行中的两个列值将一行熔化/拆分为两行,其余部分保持不变的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!
问题描述
我有一个data.table,如下:
I have a data.table as follows:
DT <- fread(
"ID country year Event_A Event_B
4 NLD 2002 0 1
5 NLD 2002 0 1
6 NLD 2006 1 1
7 NLD 2006 1 0
8 NLD 2006 1 1
9 GBR 2002 0 1
10 GBR 2002 0 0
11 GBR 2002 0 1
12 GBR 2006 1 1
13 GBR 2006 1 1",
header = TRUE)
我想将事件列投射到行上而不求和,从而创建新行。我尝试过:
I want to cast the event columns over the row without summing them, creating new rows. I tried:
meltedsessions <- melt(Exp, id.vars = -c(Event_A", "Event_B"), measure.vars = c("Event_A", "Event_B"))
我需要指定 id.vars
为负数,因为实际数据集还有另外240个需要保持不变的变量。但是,如果执行此操作,则会出现错误:
I need to specify id.vars
as a negative because the actual dataset has another 240 variables that need to stay intact. However if I do this I get the error:
Error in melt.data.table(Exp, id.vars = c("ID", "country", "year"), measure.vars = c("Event_A", :
One or more values in 'id.vars' is invalid.
我应该如何解决?
所需的输出:
DT <- fread(
"NewID ID country year Event
1 4 NLD 2002 0
2 4 NLD 2002 1
3 5 NLD 2002 0
4 5 NLD 2002 1
5 6 NLD 2006 1
6 6 NLD 2006 1
7 7 NLD 2006 1
8 7 NLD 2006 0
9 8 NLD 2006 1
10 8 NLD 2006 0
11 9 GBR 2002 1
12 9 GBR 2002 1
13 10 GBR 2002 0
14 10 GBR 2002 0
15 11 GBR 2002 0
16 12 GBR 2002 1
17 13 GBR 2006 1
18 14 GBR 2006 1
19 15 GBR 2006 1
20 16 GBR 2006 1",
header = TRUE)
推荐答案
代替 id.var <中的
-
/ code>,可以使用 setdiff
Instead of -
in id.var
, can use setdiff
library(data.table)
melt(DT, id.var = setdiff(names(DT), c("Event_A", "Event_B")),
value.name = 'Event')[, variable := NULL][order(ID)]
# ID country year Event
# 1: 4 NLD 2002 0
# 2: 4 NLD 2002 1
# 3: 5 NLD 2002 0
# 4: 5 NLD 2002 1
# 5: 6 NLD 2006 1
# 6: 6 NLD 2006 1
# 7: 7 NLD 2006 1
# 8: 7 NLD 2006 0
# 9: 8 NLD 2006 1
#10: 8 NLD 2006 1
#11: 9 GBR 2002 0
#12: 9 GBR 2002 1
#13: 10 GBR 2002 0
#14: 10 GBR 2002 0
#15: 11 GBR 2002 0
#16: 11 GBR 2002 1
#17: 12 GBR 2006 1
#18: 12 GBR 2006 1
#19: 13 GBR 2006 1
#20: 13 GBR 2006 1
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