📅 最后修改于: 2022-03-11 14:51:59.260000 🧑 作者: Mango
代码示例1
> toString(ddf$year)
[1] "1983, 1983, 1983, 1983"
>
> toString(ddf$period)
[1] "M01, M02, M03, M04"
>
> paste(toString(ddf$year), toString(ddf$period))
[1] "1983, 1983, 1983, 1983 M01, M02, M03, M04"