R减去向量-数字0答案
R减去向量-数字0答案
提问于 2015-11-06 22:44:58
我试着从另一个向量中减去两个向量，每个向量长度为7。然而，我的结果不会产生另一个向量，我只得到数字0和数据0。有什么想法吗？
#You will buy these stocks on rows/days 7, 8, 9, 15, 26, 33 and 53. (1 day after days apple dropped more than 2% )
#Assign the prices of the stocks on these days to a vector
SLB_buy = c(SLB_close[7],SLB_close[8],SLB_close[9],SLB_close[15],SLB_close[26],SLB_close[34],SLB_close[53])
SLB_buy
SLB.Close
2015-08-21 77.50
2015-08-24 73.87
2015-08-25 72.52
2015-09-02 75.41
2015-09-18 72.54
2015-09-30 68.97
2015-10-27 76.95
#You will sell these stocks on rows/days 10, 11, 12, 18, 29, 36 and 56. (3 day after purchase)
#Assign the prices of the stocks on these days to a vector
SLB_sell =c(SLB_close[10],SLB_close[11],SLB_close[12],SLB_close[18],SLB_close[29],SLB_close[36],SLB_close[56])
SLB_sell
SLB.Close
2015-08-26 70.09
2015-08-27 73.85
2015-08-28 76.06
2015-09-08 75.54
2015-09-23 71.94
2015-10-02 70.32
2015-10-30 78.16
#Your profit is equal to the sales price - buy price. Hence substract the previous vectors from each other.
SLB_sell - SLB_buy
Data:
numeric(0)
Index:
numeric(0)回答 1
Stack Overflow用户
回答已采纳
发布于 2015-11-06 23:29:44
我从剪贴板上复制了你的矢量。我为实现你想要的而做的事：
# remove SLB.Close, which is the first element of the vector.
#It might not be the case for your actual vector though.
SLB_buy<-SLB_buy[-1]
# remove the dates and transform in numeric
SLB_buy<-substring(SLB_buy, 11)
SLB_buy<-as.numeric(SLB_buy)
# depending on your actual vector the position to start substring
#(in this case 11) might vary.对第二个向量做同样的操作并减去
SLB_sell-SLB_buy页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/33576896
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