将两个日期之间的行生成到 R 中的数据框中 [英] Generate rows between two dates into a data frame in R

问题描述

我刚开始学习 R 的时间很短.我有下表

I've just started learning R for a short time. I have the following table

Name      stDte      edDte  
A    2010-05-01 2014-12-01  
B    2013-06-01 2014-02-01  

我需要把它变成这样的表格

I need to get it transformed into a table like this

Name   Dte
A      2010-05-01
A      2010-06-01
A      2010-07-01
...
A      2014-12-01
B      2013-06-01
B      2013-07-01
...
B      2014-02-01

我正在考虑将for"循环与 rbind 结合使用，但我不知道该怎么做.将不胜感激有关如何做到这一点的任何建议.提前感谢您的指导

I'm thinking about using a combination of a 'for' loop for together with rbind but I'm not sure how to go about it. Would appreciate any suggestions on how to do that. Thanks in advance for the guidance

推荐答案

由于您没有另行说明，因此此答案假定 stDte 和 edDte 列都是日期"类.

Since you don't state otherwise, this answer assumes the stDte and edDte columns are both of "Date" class.

在基础 R 中，您可以使用 Map() 创建日期序列，然后在创建新 后使用 data.frame 将新数据框组合在一起>Name 列与 rep.int().

In base R you could use Map() to create the sequence of dates, then data.frame to bring the new data frame together after creating the new Name column with rep.int().

M <- Map(seq, df$stDte, df$edDte, by = "month")
df2 <- data.frame(
    Name = rep.int(df$Name, vapply(M, length, 1L)), 
    Dte = do.call(c, M)
)    
str(df2)
# 'data.frame':    65 obs. of  2 variables:
#  $ Name: Factor w/ 2 levels "A","B": 1 1 1 1 1 1 1 1 1 1 ...
#  $ Dte : Date, format: "2010-05-01" "2010-06-01" ...
head(df2, 3)
#   Name        Dte
# 1    A 2010-05-01
# 2    A 2010-06-01
# 3    A 2010-07-01
tail(df2, 3)
#    Name        Dte
# 63    B 2013-12-01
# 64    B 2014-01-01
# 65    B 2014-02-01

或者你可以使用 data.table 包并做

Or you can use the data.table package and do

library(data.table)
setDT(df)[, .(Dte = seq(stDte, edDte, by = "month")), by = Name]

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