r - 根据特定条件拥有数据集的子集

Question

我有一个数据集，其中“年龄”的值具有不同的单位(天、月、年)。我想将其值基于日期和月份的行转换为年份。我如何在 R 中做到这一点？如果数字后没有字母，则单位为年。如果数字后面有‘D’，则单位是天(例如10D表示10天)如果数字后有‘M’，则单位为月(如5M表示5个月)。

Age <- c("33","32","44","54M","67M","34D","33D","44","77","88M","49 D","55D","11M")
ID <- c(1,2,3,4,5,6,7,8,9,10,11,12,13)
Data <- data.frame(ID,Age)

> Data
   ID  Age
1   1   33
2   2   32
3   3   44
4   4  54M
5   5  67M
6   6  34D
7   7  33D
8   8   44
9   9   77
10 10  88M
11 11 49 D
12 12  55D
13 13  11M

Answer 1

这是在 base R 中的一个快速方法:

Data$units = ifelse(grepl("M", Data$Age), "month", ifelse(grepl("D", Data$Age), "day", "year"))
Data$value = as.numeric(gsub(pattern = "[^0-9]", replacement = "", Data$Age))
Data$result = with(Data,
    ifelse(units == "year", value, 
        ifelse(units == "month", value / 12, value / 365.25)))
Data
#    ID  Age units value      result
# 1   1   33  year    33 33.00000000
# 2   2   32  year    32 32.00000000
# 3   3   44  year    44 44.00000000
# 4   4  54M month    54  4.50000000
# 5   5  67M month    67  5.58333333
# 6   6  34D   day    34  0.09308693
# 7   7  33D   day    33  0.09034908
# 8   8   44  year    44 44.00000000
# 9   9   77  year    77 77.00000000
# 10 10  88M month    88  7.33333333
# 11 11 49 D   day    49  0.13415469
# 12 12  55D   day    55  0.15058179
# 13 13  11M month    11  0.91666667