具有数据帧参数的R函数不起作用 [英] R - function which has a data frame parameter doesn't work

问题描述

我做了一个简单的代码，它可以将索引号改为name

$ $ $ $ codehange_name = function（x）{
valid_user [match（x，valid_user $ id），'name']
}

并将此函数应用于data.frame。

Data.frame名称为'ga.screen'，列名为'dimension1'。

  ga.screen [，'dimension1'] = sapply（ga.screen [，'dimension1']，change_name）
  
  
 
 
接下来我想让这个代码函数
 
 
  readable_user_id = function（data，col）{
 data [，col] = sapply（data [，col]，change_name）
} 
 readable_user_id（ga.screen，'dimension1'）
  
这是完全相同的代码，但后者不起作用！
 
 
 
为什么会发生这种情况？这是一个 sapply 问题，它不起作用？或者这是 data.frame 问题，它不能作为参数传递？
解决方案
你的函数应该返回修改后的数据，尝试
 可读的用户ID =函数（data，col）{
 data [，col] = sapply（data [，col]，change_name）
 data 
} 
  
 
I make a simple code which can change the index number to name
change_name = function(x) {
  valid_user[match(x, valid_user$id),'name']
}
and apply this function to data.frame.

Data.frame name is 'ga.screen', and the column name is 'dimension1'.
ga.screen[, 'dimension1'] =sapply(ga.screen[, 'dimension1'], change_name)
It works well.

And next I want to make this code function which is be able to apply various case.
readable_user_id = function(data, col) {
  data[, col] = sapply(data[, col], change_name)
}
readable_user_id(ga.screen, 'dimension1')
This is totally same code but the latter one doesn't work!

Why this happens? Is this a sapply problem which doesn't work in function? or Is this data.frame problem which can't be passed as parameter?
解决方案
Your function should return the modified data, try
readable_user_id = function(data, col) {
   data[, col] = sapply(data[, col], change_name)
   data
}


                        
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