我开始使用RStudio笔记本,我仍然试图了解一些工作原理.我不明白为什么在执行与消息完全无关的代码时会保留并显示某些生成的警告消息.例如,我有一个包含多个块的文档,其中最后一个生成警告
> warnings()
Warning messages:
1: Unknown or uninitialised column: 'perc.goal.met.period'.
2: Unknown or uninitialised column: 'perc.goal.met.period'.
3: Unknown or uninitialised column: 'perc.goal.met.period'.
4: Unknown or uninitialised column: 'perc.goal.met.period'.
5: Unknown or uninitialised column: 'perc.goal.met.period'.
6: Unknown or uninitialised column: 'perc.goal.met.period'.
7: Unknown or uninitialised column: 'perc.goal.met.period'.
8: Unknown or uninitialised column: 'perc.goal.met.period'.
9: Unknown or uninitialised column: 'perc.goal.met.period'.
10: Unknown or uninitialised column: 'perc.goal.met.period'.
11: Unknown or uninitialised column: 'perc.goal.met.period'.
12: Unknown or uninitialised column: 'perc.goal.met.period'.
13: Unknown or …我想使用 terra 将一些栅格堆叠在列表中。
这过去在光栅中非常容易工作，因为它可以列表stack()。然而，这在陆地上已经不可能了。请参阅下面的示例：
r1 <- raster(nrows = 1, ncols = 1, res = 0.5, xmn = -1.5, xmx = 1.5, ymn = -1.5, ymx = 1.5, vals = 0.1)
r2 <- raster(nrows = 1, ncols = 1, res = 0.5, xmn = -1.5, xmx = 1.5, ymn = -1.5, ymx = 1.5, vals = 0.2)
r_list <- list(r1, r2)
r_stack <- stack(r_list)
栅格堆栈中的结果：
class : RasterStack
dimensions : 6, 6, 36, 2 (nrow, ncol, ncell, nlayers)
resolution …我想使用 dplyr 比较分组 data.frame 内的值，并创建一个虚拟变量或类似的变量，指示哪个更大。想不通！
这是一些可重现的代码：
table <- structure(list(species = structure(c(1L, 1L, 1L, 2L, 2L, 2L), .Label = c("Adelophryne adiastola",
"Adelophryne gutturosa"), class = "factor"), scenario = structure(c(3L,
1L, 2L, 3L, 1L, 2L), .Label = c("future1", "future2", "present"
), class = "factor"), amount = c(5L, 3L, 2L, 50L, 60L, 40L)), .Names = c("species",
"scenario", "amount"), class = "data.frame", row.names = c(NA,
-6L))
> table
species scenario amount
1 Adelophryne adiastola present 5
2 Adelophryne adiastola future1 3
3 Adelophryne adiastola …