如何做一个数据帧逐行计算不使用for循环 - R的

Question

这是我的目标来计算输出：

这是我经历的每一行迭代代码数据框，做计算，这我知道是不是第一行做

STOCKsbyQuarter_LOCF_Ticker <- subset(STOCKsbyQuarter_LOCF, STOCKsbyQuarter_LOCF$Ticker == input$STOCKTickers) 

for(i in 1:length(STOCKsbyQuarter_LOCF_Ticker$ROIC)){  
    STOCKsbyQuarter_LOCF_Ticker$ROICDelta <- (STOCKsbyQuarter_LOCF_Ticker$ROIC[i+1] - STOCKsbyQuarter_LOCF_Ticker$ROIC[1])/
               (STOCKsbyQuarter_LOCF_Ticker$date[i+1] - STOCKsbyQuarter_LOCF_Ticker$date[1])  
} 

Answer 1

df <- STOCKsbyQuarter_LOCF_Ticker 
df$ROIC_Delta <- (df$ROIC - df$ROIC[1])/(df$Date - df$Date[1]) 

ROIC_Delta将是的最佳方式3210。您可以将其替换为适当的值。

Answer 2

library(data.table) 
dt = setDT(STOCKsbyQuarter_LOCF_Ticker) 

dt[ , "ROIC Delta" := (ROIC - shift(ROIC))/as.numeric(difftime(Date, shift(Date),units = c("days")))]