问题描述
考虑以下示例:
library(tidyverse)
set.seed(1)
forecast::forecast
x <- cumsum(rnorm(10))
y1 <- arima(x, order = c(1, 0, 0))
y2 <- x %>% arima(order = c(1, 0, 0))
length(fitted(y1))
[1] 10
length(fitted(y2))
[1] 0
对象y1和y2几乎相同，唯一的例外是槽call和series.所以我想这就是 fitted 函数开始神奇的地方.
The objects y1and y2are almost identical, the only exceptions being the slots calland series. So I guess that is where the fitted functions starts its magic.
我真的很想使用 y1 而不是 y2.有谁知道 fitted 的替代函数会产生相同的结果吗?
I would really like to work with y1 instead of y2.Does anyone know an alternative function to fitted which produces the same result?
如果 forecast 包没有加载到命名空间中(例如通过 forecast::forecast)，则不会出现上述错误".我不知道将包加载到命名空间会改变某些函数的行为.
The above "bug" does not appear if the forecast package is not loaded into namespace (via eg. forecast::forecast).I wasnt aware that loading a package into namespace changes the behaviour of some functions.
由于代码似乎不可重现，因此我添加了我的 `sessionInfo()´
since the code seems not to be reproducible I add my `sessionInfo()´
R version 3.5.2 (2018-12-20)
Platform: x86_64-w64-mingw32/x64 (64-bit)
Running under: Windows 7 x64 (build 7601) Service Pack 1
Matrix products: default
locale:
[1] LC_COLLATE=German_Austria.1252 LC_CTYPE=German_Austria.1252 LC_MONETARY=German_Austria.1252 LC_NUMERIC=C LC_TIME=German_Austria.1252
attached base packages:
[1] stats graphics grDevices utils datasets methods base
other attached packages:
[1] forcats_0.4.0 stringr_1.3.1 dplyr_0.8.0.1 purrr_0.3.0 readr_1.3.1 tidyr_0.8.2 tibble_2.0.1 ggplot2_3.1.0 tidyverse_1.2.1 magrittr_1.5
loaded via a namespace (and not attached):
[1] zoo_1.8-4 tidyselect_0.2.5 urca_1.3-0 aTSA_3.1.2 haven_2.0.0 lattice_0.20-38 colorspace_1.4-0 generics_0.0.2 yaml_2.2.0 utf8_1.1.4 rlang_0.3.1 pillar_1.3.1
[13] withr_2.1.2 glue_1.3.0 forecast_8.5 TTR_0.23-4 modelr_0.1.2 readxl_1.2.0 plyr_1.8.4 quantmod_0.4-13 timeDate_3043.102 munsell_0.5.0 gtable_0.2.0 cellranger_1.1.0
[25] rvest_0.3.2 tseries_0.10-46 lmtest_0.9-36 parallel_3.5.2 curl_3.3 fansi_0.4.0 broom_0.5.1 xts_0.11-2 Rcpp_1.0.0 scales_1.0.0 backports_1.1.3 jsonlite_1.6
[37] fracdiff_1.4-2 hms_0.4.2 stringi_1.3.1 grid_3.5.2 cli_1.0.1 quadprog_1.5-5 tools_3.5.2 lazyeval_0.2.1 crayon_1.3.4 pkgconfig_2.0.2 xml2_1.2.0 lubridate_1.7.4
推荐答案
您所发现的是非标准评估导致的问题，在 关于magrittr 管道的技术说明:
What you've identified is a problem caused by non-standard evaluation, which is briefly mentioned in the technical note about the magrittr pipe:
magrittr 管道操作员使用非标准评估.他们捕捉他们的输入并检查它们以找出如何进行.首先一个函数是从所有单独的右手边产生的表达式，然后通过应用这个函数得到结果到左侧.对于大多数目的，人们可以忽略微妙的magrittr 评估的各个方面，但某些函数可能会捕获它们的调用环境，因此使用运算符不会完全正确相当于没有管道操作符的标准调用".
如果您查看 fitted 的 arima 版本的源代码，您会发现您认为 call 属性是必不可少的是正确的到方法的操作:
If you look at the source for arima version of fitted you can see that you were correct in thinking that the call attribute is essential to the method's operation:
getAnywhere(fitted.Arima)
A single object matching ‘fitted.Arima’ was found
It was found in the following places
registered S3 method for fitted from namespace TSA
namespace:TSA
with value
function (object, ...)
{
fitted = eval(object$call$x) - object$residuals
fitted
}
<bytecode: 0x000000001e8ff4d8>
<environment: namespace:TSA>
这篇关于R中magrittr和arima的兼容性问题的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！