Question

我想使用dplyr::mutate将p值添加到数据框但是它不起作用，我无法理解为什么。

这有效：

my_add<-function(x, y) x + y
str(my_add(5, 15))
#> num 20

df <- data.frame(success=c(5,8,4), fail=c(15,13,18))
mutate(df, total=my_add(success, fail))
#>   success fail total
#> 1       5   15    20
#> 2       8   13    21
#>13       4   18    22

但这不是：

my_binom <- function(x, y) binom.test(x, y)$"p.value"
str(my_binom(5, 20))
#> num 0.0414

df <- data.frame(success=c(5,8), total=c(20,21))
mutate(df, p_value=my_binom(success, total))
#>   success total   p_value
#> 1       5    20 0.5810547
#> 2       8    21 0.5810547

df <- data.frame(success=c(5,8,4), total=c(20,21,22))
mutate(df, p_value=my_binom(success, total))
#> Error in mutate_impl(.data, dots) : 
#>   Evaluation error: incorrect length of 'x'.

两个函数都使用相同的输入并返回一个数字，所以我无法解决这个差异。有人可以告诉我发生了什么事吗？谢谢！

会话信息：

sessionInfo()
#> R version 3.4.1 (2017-06-30)
#> Platform: x86_64-apple-darwin15.6.0 (64-bit)
#> Running under: OS X El Capitan 10.11.6
#> 
#> Matrix products: default
#> BLAS: /System/Library/Frameworks/Accelerate.framework/Versions/A/Frameworks/vecLib.framework/Versions/A/libBLAS.dylib
#> LAPACK: /Library/Frameworks/R.framework/Versions/3.4/Resources/lib/libRlapack.dylib
#> 
#> locale:
#> [1] en_GB.UTF-8/en_GB.UTF-8/en_GB.UTF-8/C/en_GB.UTF-8/en_GB.UTF-8
#> 
#> attached base packages:
#> [1] stats     graphics  grDevices utils     datasets  methods   base     
#> 
#> other attached packages:
#> [1] bindrcpp_0.2 dplyr_0.7.4 
#> 
#> loaded via a namespace (and not attached):
#>  [1] compiler_3.4.1   magrittr_1.5     assertthat_0.2.0 R6_2.2.2         tools_3.4.1     
#>  [6] glue_1.1.1       tibble_1.3.4     yaml_2.1.14      Rcpp_0.12.14     pkgconfig_2.0.1 
#> [11] rlang_0.1.2      bindr_0.1

Answer 1

mutate(df, p_value = purrr::map2(success, total, my_binom))

dplyr :: mutate中的函数行为不一致

1 个答案: