R：如何通过操作日期时间列在数据框中添加行

Question

我有一个 table 的参考股票代码，看起来像这样

我想调查每个“展示日期”前后的价格变化。

例如，我想为一个现有行添加 2 个新行，显示日期为 -1 和 + 1 天，本质上是将 table 膨胀 3 次。除了确保正确添加符号外，将所有其他列留空。

That is: 
for first row             ZTS 2017-01-09 Buy 
I want to add 2 more rows ZTS 2017-01-08
                          ZTS 2017-01-10

For the next row          ZTS 2016-11-02 Buy 
add 2 more rows           ZTS 2016-11-01 
                          ZTS 2016-11-03 
etc...

我阅读了有关 add_rows() 的内容，但该函数不允许我这样做。这个 post 也没有解决

有人能做到吗？通常我只处理列.....

>dput(head(sanitised))
structure(list(Company = c("Agilent Technologies ", "Agilent 
Technologies ", 
"Agilent Technologies ", "Agilent Technologies ", "Agilent 
Technologies ", 
"Alcoa "), symbol = c("A", "A", "A", "A", "A", "AA"), showdate = 
c("2021-08-18", 
"2020-04-16", "2017-11-17", "2017-03-23", "2016-05-13", "2016-10- 
07"
), call = c("Buy", "Buy", "Buy", "Buy", "Buy", "Buy"), 
show_segment = c("Guest Interview", 
"Guest Interview", "Discussed Stock", "Featured Stock", 
"Discussed Stock", 
"Discussed Stock"), call_price = c("3.02", ".75", ".79", 
".18", ".49", ".37"), current_returns = c("+0.0%", 
"+0.0%", 
"+0.0%", "+0.0%", "+0.0%", "+0.0%"), day_7_returns = c("", "", 
"", "+0.3%", "+5.7%", "-15.7%"), day_14_returns = c("", "", "", 
"-0.1%", "", ""), day_30_returns = c("", "", "", "", "+6.8%", 
"-19.7%")), row.names = c(NA, 6L), class = "data.frame")

Answer 1

这是一种使用 split 和 map_dfr 的方法。我假设对于添加的行，大多数列中的值将是 NA。您当然可以在 add_row.

中添加其他值

library(tidyverse)

sanitised %>%
  mutate(showdate = as.Date(showdate, format = '%Y-%m-%d')) %>%
  split(list(sanitised$symbol, sanitised$showdate)) %>%
  map_dfr(function(x) {
    x %>%
      # any other columns you want to keep could go in here as well
      add_row(symbol = x$symbol, showdate = x$showdate - 1) %>%
      add_row(symbol = x$symbol, showdate = x$showdate + 1)
  })

Answer 2

这是一个带有循环的基本 R 方法，假设“symbol”是唯一复制的列：

x$showdate <- as.Date(x$showdate)
for(i in rownames(x)){
    x[paste0(i, ".", 1), "showdate"] <- x[i, "showdate"] - 1
    x[paste0(i, ".", 2), "showdate"] <- x[i, "showdate"] + 1
    x[paste0(i, ".", 1), "symbol"] <- x[i, "symbol"]
    x[paste0(i, ".", 2), "symbol"] <- x[i, "symbol"]
}
x <- x[order(rownames(x)), ]

R：如何通过操作日期时间列在数据框中添加行

R: how to add rows in dataframe by manipulating a datetime column

datetime

r

dataframe

data-wrangling