使用“mapply”创建输出

Question

我想为每个条目创建一个带有要点的输出

数据

我的数据框中有一行（而且只有一行）：

structure(list(Dimensions = 2L, Continuity = structure(2L, .Label = c("", 
"continuous"), class = "factor"), Differentiability = structure(2L, .Label = c("", 
"differentiable", "non-differentiable"), class = "factor"), Convexity = structure(2L, .Label = c("", 
"convex", "non-convex"), class = "factor"), Modality = structure(3L, .Label = c("", 
"multimodal", "unimodal"), class = "factor"), Separability = structure(2L, .Label = c("", 
"non-separable", "non-separable,", "separable"), class = "factor"), 
    Scalability = structure(2L, .Label = c("", "non-scalable", 
    "scalable"), class = "factor"), Parametric = FALSE, Random = FALSE), row.names = 2L, class = "data.frame")

方法

mapply(function(x, y) cat("* ", y, ": ", as.character(x), "\n"), Descr, names(Descr))

期望的输出

* Dimensions :  2
* Continuity :  continuous
* Differentiability :  differentiable
* Convexity :  convex
* Modality :  unimodal
* Separability :  non-separable
* Scalability :  non-scalable
* Parametric :  FALSE
* Random :  FALSE

实际结果

我已经很接近我想要的了。但是，R 不仅会打印所需的部分，还会在之后添加所有列的列表。所以输出看起来像这样：

*  Dimensions :  2 
*  Continuity :  continuous 
*  Differentiability :  differentiable 
*  Convexity :  convex 
*  Modality :  unimodal 
*  Separability :  non-separable 
*  Scalability :  non-scalable 
*  Parametric :  FALSE 
*  Random :  FALSE 
$Dimensions
NULL

$Continuity
NULL

$Differentiability
NULL

$Convexity
NULL

$Modality
NULL

$Separability
NULL

$Scalability
NULL

$Parametric
NULL

$Random
NULL

不仅仅是一个有效的解决方案，如果有人能给我提示这里发生了什么，我将不胜感激。

Answer 1

R 中的 *apply 函数总是有一个输出。

解决这个问题的一种方法是用 invisible:

调用它们

invisible(mapply(function(x, y) cat("* ", y, ": ", as.character(x), "\n"), Descr, names(Descr)))
*  Dimensions :  2 
*  Continuity :  continuous 
*  Differentiability :  differentiable 
*  Convexity :  convex 
*  Modality :  unimodal 
*  Separability :  non-separable 
*  Scalability :  non-scalable 
*  Parametric :  FALSE 
*  Random :  FALSE

purrr 包具有 walk 组函数，原因如下：

library(purrr)
walk2(Descr,names(Descr), function(x, y) cat("* ", y, ": ", as.character(x), "\n"))
*  Dimensions :  2 
*  Continuity :  continuous 
*  Differentiability :  differentiable 
*  Convexity :  convex 
*  Modality :  unimodal 
*  Separability :  non-separable 
*  Scalability :  non-scalable 
*  Parametric :  FALSE 
*  Random :  FALSE

Answer 2

一个选项是将输出分配给一个变量：

x <- mapply(function(x, y) cat("* ", y, ": ", as.character(x), "\n"), Descr, names(Descr))

使用“mapply”创建输出

Use ´mapply´ to create an output

r

mapply

数据

方法

期望的输出

实际结果