我有一个面板数据集如下 . 但实际数据集有数千个观测值 . 我想创建14个facotors作为1984-1998(15年)的新专栏“Year_dum” . 我在r中搜索创建虚拟变量,但是找不到使用年整数的方法 . 谁能帮我在r做这个 .
+--------+------+------+------+----------+
| Time | year | Firm | Prod | Year_dum |
+--------+------+------+------+----------+
| Jan-84 | 1984 | A | 28.2 | 0 |
| Feb-84 | 1984 | A | 26.6 | 0 |
| Mar-84 | 1984 | A | 30.3 | 0 |
| Apr-85 | 1985 | A | 33.2 | 1 |
| May-85 | 1985 | A | 30.1 | 1 |
| Jun-85 | 1985 | A | 28.3 | 1 |
| Jan-84 | 1984 | B | 28.6 | 0 |
| Feb-84 | 1984 | B | 28.9 | 0 |
| Mar-84 | 1984 | B | 28.1 | 0 |
| Oct-84 | 1984 | C | 28.8 | 0 |
| Nov-85 | 1985 | C | 31.6 | 1 |
| Dec-86 | 1986 | C | 26.9 | 2 |
| Jan-89 | 1989 | C | 28.6 | 5 |
| Feb-98 | 1998 | C | 29.6 | 14 |
+--------+------+------+------+----------+
可以使用以下dput访问此简单数据集 .
structure(list(Time = structure(c(6L, 4L, 9L, 2L, 10L, 8L, 6L,
4L, 9L, 12L, 11L, 3L, 7L, 5L, 1L, 1L, 1L), .Label = c("", "Apr-85",
"Dec-86", "Feb-84", "Feb-98", "Jan-84", "Jan-89", "Jun-85", "Mar-84",
"May-85", "Nov-85", "Oct-84"), class = "factor"), year = c(1984L,
1984L, 1984L, 1985L, 1985L, 1985L, 1984L, 1984L, 1984L, 1984L,
1985L, 1986L, 1989L, 1998L, NA, NA, NA), Firm = structure(c(2L,
2L, 2L, 2L, 2L, 2L, 3L, 3L, 3L, 4L, 4L, 4L, 4L, 4L, 1L, 1L, 1L
), .Label = c("", "A", "B", "C"), class = "factor"), Prod = c(28.2,
26.6, 30.3, 33.2, 30.1, 28.3, 28.6, 28.9, 28.1, 28.8, 31.6, 26.9,
28.6, 29.6, NA, NA, NA), Year_dum = c(0L, 0L, 0L, 1L, 1L, 1L,
0L, 0L, 0L, 0L, 1L, 2L, 5L, 14L, NA, NA, NA)), .Names = c("Time",
"year", "Firm", "Prod", "Year_dum"), class = "data.frame", row.names = c(NA,
-17L))
3 回答
我们可以尝试
或者使用
match
例如,您可以使用
dummies
包(首先使用install.packages("dummies")
安装它) . 一个例子:以下是仅使用
base
的示例: