Question

寻找关于如何使用dplyr的mutate_if语句检查我是否需要将列转换为因子变量的一些建议。

这个功能说明了我试图做的事情。问题是，当我想为＆＃34; max_value＆＃34;传递某些内容时，正确的语法是什么？我的函数中的参数？

不起作用 - 我尝试在功能中更改参数。

funct_change <- function(x, max_value ){
  max(x, na.rm = TRUE) >max_value 
  }


mtcars %>% mutate_if( funct_change(max_value=30), as.character) %>% glimpse()

工作 - 我对参数进行了硬编码

funct_change <- function(x, max_value=30 ){
      max(x, na.rm = TRUE) >max_value 
      }


    mtcars %>% mutate_if( funct_change, as.character) %>% glimpse()

Answer 1

如果您要向.predicate mutate_if以及.funs dplyr中出现的其他地方~提供除功能名称以外的任何内容，您需要执行以下操作之一：

将函数包装在匿名函数中
使用简写公式语法...基本上做同样的事情。
此处不适用，但有时.funs允许您向max_value = 30添加额外的参数，因此您可以将mutate作为参数提供给mutate_if。对于.predicate，仅适用于要应用的功能，而不适用于funct_change <- function(x, max_value){ max(x, na.rm = TRUE) > max_value } library(dplyr) mtcars %>% mutate_if(function(x) funct_change(x, 30), as.character) %>% glimpse() #> Observations: 32 #> Variables: 11 #> $ mpg <chr> "21", "21", "22.8", "21.4", "18.7", "18.1", "14.3", "24.4... #> $ cyl <dbl> 6, 6, 4, 6, 8, 6, 8, 4, 4, 6, 6, 8, 8, 8, 8, 8, 8, 4, 4, ... #> $ disp <chr> "160", "160", "108", "258", "360", "225", "360", "146.7",... #> $ hp <chr> "110", "110", "93", "110", "175", "105", "245", "62", "95... #> $ drat <dbl> 3.90, 3.90, 3.85, 3.08, 3.15, 2.76, 3.21, 3.69, 3.92, 3.9... #> $ wt <dbl> 2.620, 2.875, 2.320, 3.215, 3.440, 3.460, 3.570, 3.190, 3... #> $ qsec <dbl> 16.46, 17.02, 18.61, 19.44, 17.02, 20.22, 15.84, 20.00, 2... #> $ vs <dbl> 0, 0, 1, 1, 0, 1, 0, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 1, 1, ... #> $ am <dbl> 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, ... #> $ gear <dbl> 4, 4, 4, 3, 3, 3, 3, 4, 4, 4, 4, 3, 3, 3, 3, 3, 3, 4, 4, ... #> $ carb <dbl> 4, 4, 1, 1, 2, 1, 4, 2, 2, 4, 4, 3, 3, 3, 4, 4, 4, 1, 2, ... mtcars %>% mutate_if(~ funct_change(., 30), as.character) %>% glimpse() #> Observations: 32 #> Variables: 11 #> $ mpg <chr> "21", "21", "22.8", "21.4", "18.7", "18.1", "14.3", "24.4... #> $ cyl <dbl> 6, 6, 4, 6, 8, 6, 8, 4, 4, 6, 6, 8, 8, 8, 8, 8, 8, 4, 4, ... #> $ disp <chr> "160", "160", "108", "258", "360", "225", "360", "146.7",... #> $ hp <chr> "110", "110", "93", "110", "175", "105", "245", "62", "95... #> $ drat <dbl> 3.90, 3.90, 3.85, 3.08, 3.15, 2.76, 3.21, 3.69, 3.92, 3.9... #> $ wt <dbl> 2.620, 2.875, 2.320, 3.215, 3.440, 3.460, 3.570, 3.190, 3... #> $ qsec <dbl> 16.46, 17.02, 18.61, 19.44, 17.02, 20.22, 15.84, 20.00, 2... #> $ vs <dbl> 0, 0, 1, 1, 0, 1, 0, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 1, 1, ... #> $ am <dbl> 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, ... #> $ gear <dbl> 4, 4, 4, 3, 3, 3, 3, 4, 4, 4, 4, 3, 3, 3, 3, 3, 3, 4, 4, ... #> $ carb <dbl> 4, 4, 1, 1, 2, 1, 4, 2, 2, 4, 4, 3, 3, 3, 4, 4, 4, 1, 2, ...。

def example_plot(ax, somedata, somedata2, title, xlab, ylab, fontsize=12):

    ax.plot(somedata, color='b')
    ax.plot(somedata2, color='g')
    ax.locator_params(nbins=3)
    ax.set_xlabel(xlab, fontsize=8)
    ax.set_ylabel(ylab, fontsize=10)
    ax.set_title(title, fontsize=10)

import matplotlib.pyplot as plt
import numpy as np 
fig, ((ax1, ax2), (ax3, ax4)) = plt.subplots(nrows=2, ncols=2)
ax1.grid(color='r', linestyle='-', linewidth=1)
ax2.grid(color='r', linestyle='-', linewidth=1)
ax3.grid(color='r', linestyle='-', linewidth=1)
ax4.grid(color='r', linestyle='-', linewidth=1)

example_plot(ax1,cumulative1,survival1, t1, xlbl1, ylbl1) 
example_plot(ax2,cumulative2,survival2, t2, xlbl2, ylbl2)
example_plot(ax3,cumulative3,survival3, t3, xlbl3, ylbl3)
example_plot(ax4,cumulative4,survival4, t4, xlbl4, ylbl4)

plt.tight_layout(pad= 0.4, w_pad= 0.5, h_pad = 1.0)

由reprex package（v0.2.0）创建于2018-04-10。

Mutate_if语法帮助 - 如何在谓词条件

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