我有一个数据框，并根据两个日期之间的差异重复行：日期（样本收集日期）和孵化（出生日期）使用以下代码。差异（基本上是几个月的寿命）从4-12个月不等：
library(zoo)
test$difference <- 12 * as.numeric(as.yearmon(test$Date) - as.yearmon(test$hatch))
test$difference <- ceiling(test$difference)
test2 <- test[rep(row.names(test), test$difference),]
我需要从孵化日期开始为每个样本创建一个序列（每个样本都有一个唯一的序列号，sn），以1个月为增量增加，长度等于差异列中的值。我尝试了一个循环，但我无法弄清楚如何对它进行说明，因为我对R.很新。
目前日期格式为％Y-％m-％d，但我只对月份和年份分组感兴趣。
任何见解都非常有用：）
structure(list(Sex = structure(c(3L, 3L, 3L, 3L, 3L, 3L, 3L,
3L, 3L, 3L, 3L, 3L, 3L, 3L, 3L), .Label = c("F", "J", "M"), class = "factor"),
Maturity = c(5L, 5L, 5L, 5L, 5L, 5L, 5L, 5L, 5L, 5L, 5L,
5L, 5L, 5L, 5L), XLength = c(12, 12, 12, 12, 12, 12, 12,
12, 12, 16.5, 16.5, 16.5, 16.5, 16.5, 16.5), Weight = c(44.1,
44.1, 44.1, 44.1, 44.1, 44.1, 44.1, 44.1, 44.1, 73.6, 73.6,
73.6, 73.6, 73.6, 73.6), Ringcount = c(232L, 232L, 232L,
232L, 232L, 232L, 232L, 232L, 232L, 225L, 225L, 225L, 225L,
225L, 225L), Date = structure(c(10480, 10480, 10480, 10480,
10480, 10480, 10480, 10480, 10480, 10480, 10480, 10480, 10480,
10480, 10480), class = "Date"), hatch = structure(c(10248,
10248, 10248, 10248, 10248, 10248, 10248, 10248, 10248, 10255,
10255, 10255, 10255, 10255, 10255), class = "Date"), sn = c(1,
1, 1, 1, 1, 1, 1, 1, 1, 2, 2, 2, 2, 2, 2), difference = c(9,
9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9)), .Names = c("Sex",
"Maturity", "XLength", "Weight", "Ringcount", "Date", "hatch",
"sn", "difference"), row.names = c(NA, 15L), class = "data.frame")
答案 0 :(得分：1)
1）假设您要使用test添加包含日期的新列，我们可以编写以下内容。它不使用任何包。
Seq <- function(h) seq(h[1], length = length(h), by = "month")
transform(test, dates = ave(hatch, sn, FUN = Seq))
，并提供：
Sex Maturity XLength Weight Ringcount Date hatch sn difference dates
1 M 5 12.0 44.1 232 1998-09-11 1998-01-22 1 9 1998-01-22
2 M 5 12.0 44.1 232 1998-09-11 1998-01-22 1 9 1998-02-22
3 M 5 12.0 44.1 232 1998-09-11 1998-01-22 1 9 1998-03-22
4 M 5 12.0 44.1 232 1998-09-11 1998-01-22 1 9 1998-04-22
5 M 5 12.0 44.1 232 1998-09-11 1998-01-22 1 9 1998-05-22
6 M 5 12.0 44.1 232 1998-09-11 1998-01-22 1 9 1998-06-22
7 M 5 12.0 44.1 232 1998-09-11 1998-01-22 1 9 1998-07-22
8 M 5 12.0 44.1 232 1998-09-11 1998-01-22 1 9 1998-08-22
9 M 5 12.0 44.1 232 1998-09-11 1998-01-22 1 9 1998-09-22
10 M 5 16.5 73.6 225 1998-09-11 1998-01-29 2 9 1998-01-29
11 M 5 16.5 73.6 225 1998-09-11 1998-01-29 2 9 1998-03-01
12 M 5 16.5 73.6 225 1998-09-11 1998-01-29 2 9 1998-03-29
13 M 5 16.5 73.6 225 1998-09-11 1998-01-29 2 9 1998-04-29
14 M 5 16.5 73.6 225 1998-09-11 1998-01-29 2 9 1998-05-29
15 M 5 16.5 73.6 225 1998-09-11 1998-01-29 2 9 1998-06-29
2）或者，如果您只想要年月和月份，请使用动物园的yearmon课程。
library(zoo)
Seq_ym <- function(h) h[1] + (seq_along(h) - 1) / 12
transform(test, dates = ave(as.yearmon(hatch), sn, FUN = Seq_ym))
，并提供：
Sex Maturity XLength Weight Ringcount Date hatch sn difference dates
1 M 5 12.0 44.1 232 1998-09-11 1998-01-22 1 9 Jan 1998
2 M 5 12.0 44.1 232 1998-09-11 1998-01-22 1 9 Feb 1998
3 M 5 12.0 44.1 232 1998-09-11 1998-01-22 1 9 Mar 1998
4 M 5 12.0 44.1 232 1998-09-11 1998-01-22 1 9 Apr 1998
5 M 5 12.0 44.1 232 1998-09-11 1998-01-22 1 9 May 1998
6 M 5 12.0 44.1 232 1998-09-11 1998-01-22 1 9 Jun 1998
7 M 5 12.0 44.1 232 1998-09-11 1998-01-22 1 9 Jul 1998
8 M 5 12.0 44.1 232 1998-09-11 1998-01-22 1 9 Aug 1998
9 M 5 12.0 44.1 232 1998-09-11 1998-01-22 1 9 Sep 1998
10 M 5 16.5 73.6 225 1998-09-11 1998-01-29 2 9 Jan 1998
11 M 5 16.5 73.6 225 1998-09-11 1998-01-29 2 9 Feb 1998
12 M 5 16.5 73.6 225 1998-09-11 1998-01-29 2 9 Mar 1998
13 M 5 16.5 73.6 225 1998-09-11 1998-01-29 2 9 Apr 1998
14 M 5 16.5 73.6 225 1998-09-11 1998-01-29 2 9 May 1998
15 M 5 16.5 73.6 225 1998-09-11 1998-01-29 2 9 Jun 1998