R:在数据表中使用quantmod的Delt [英] R: Using quantmod's Delt in a data.table
问题描述
按照 R data.table返回计算和设置()
我想问我如何使用 Delt()
从库(quantmod)
在 data.table()
中的时间序列。
到目前为止,感谢Frank,我有:
set.seed(42)
DT< ; - data.table(
ticker = rep(letters,each = 5),
priceA = runif(5 * 26 ^ 2),
priceB = runif(5 * 26 ^ 2) )
DT [,粘贴('返回',LETTERS [1:2],sep =''):= {
lapply(.SD,function(x){
old< - head(x,-1)
new< - tail(x,-1)
c(NA,(new-old)/ old)
})
},by = ticker,.SDcols = grep('^ price',names(DT))]
结果(对于此种子值)为:
ticker priceA priceB returnsA returnedB
1:a 0.9148060 0.7956245 NA NA
2:a 0.9370754 0.9314941 0.02434327 0.1707710
3:a 0.2861395 0.6269996 -0.69464620 -0.3268883
4:a 0.8304476 0.1666758 1.90224707 -0.7341691
5:a 0.6417455 0.6483800 -0.22722939 2.8900659
---
3376:z 0.2887293 0.3473923 -0.54132570 -0.3514041
3377:z 0.9013438 0.1788842 2.12176058 -0.4850656
3378:z 0.3126429 0.7648157 -0.65313686 3.2754788
3379 :z 0.8791381 0.1300418 1.81195584 -0.3299698
3380:z 0.8160158 0.8159330 -0.07180019 5.2743905
我使用 Delt()
(或类似的%更改函数)而不是 function(x){
p>
old < ,-1)
new< - tail(x,-1)
c(NA,(new-old)/ old)
}
很多谢谢!
Delt
到一个简单的向量:
DT [,
paste('returns',LETTERS [1:2],sep =''):= lapply(.SD,function(x)c(Delt(x))),
by = ticker,.SDcols = grep('^ price',names(DT))
]
/ p>
股票价格A股价B回报A回报B
1:a 0.9148060 0.7956245 NA NA
2:a 0.9370754 0.9314941 0.02434327 0.1707710
3:a 0.2861395 0.6269996 -0.69464620 -0.3268883
4:a 0.8304476 0.1666758 1.90224707 -0.7341691
5:a 0.6417455 0.6483800 -0.22722939 2.8900659
---
Following R data.table Return calculation and set()
I would like to ask how I can use Delt()
from library(quantmod)
to find returns for a time-series in a data.table()
.
So far, thanks to Frank, I have:
set.seed(42)
DT <- data.table(
ticker=rep(letters,each=5),
priceA=runif(5*26^2),
priceB=runif(5*26^2))
DT[,paste('returns',LETTERS[1:2],sep=''):={
lapply(.SD,function(x){
old <- head(x,-1)
new <- tail(x,-1)
c(NA,(new-old)/old)
})
},by=ticker,.SDcols=grep('^price',names(DT))]
The result (for this seed value) is:
ticker priceA priceB returnsA returnsB
1: a 0.9148060 0.7956245 NA NA
2: a 0.9370754 0.9314941 0.02434327 0.1707710
3: a 0.2861395 0.6269996 -0.69464620 -0.3268883
4: a 0.8304476 0.1666758 1.90224707 -0.7341691
5: a 0.6417455 0.6483800 -0.22722939 2.8900659
---
3376: z 0.2887293 0.3473923 -0.54132570 -0.3514041
3377: z 0.9013438 0.1788842 2.12176058 -0.4850656
3378: z 0.3126429 0.7648157 -0.65313686 3.2754788
3379: z 0.8791381 0.1300418 1.81195584 -0.8299698
3380: z 0.8160158 0.8159330 -0.07180019 5.2743905
How can I use Delt()
(or a similar %change function) instead of function(x){
old <- head(x,-1)
new <- tail(x,-1)
c(NA,(new-old)/old)
}
??
Many many thanks!
You just need to convert the return value of Delt
to a simple vector:
DT[,
paste('returns',LETTERS[1:2],sep=''):=lapply(.SD,function(x) c(Delt(x))),
by=ticker,.SDcols=grep('^price',names(DT))
]
This produces:
ticker priceA priceB returnsA returnsB
1: a 0.9148060 0.7956245 NA NA
2: a 0.9370754 0.9314941 0.02434327 0.1707710
3: a 0.2861395 0.6269996 -0.69464620 -0.3268883
4: a 0.8304476 0.1666758 1.90224707 -0.7341691
5: a 0.6417455 0.6483800 -0.22722939 2.8900659
---
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