R 如何用另一个数据帧的值替换值? [英] R How can I replace values with values of another dataframe?

问题描述

我有一个巨大的数据框 df 在列a"中包含数字我还有一个数据框 name 包含与这些数字对应的名称.

I have a huge dataframe df containing Numbers in the column "a" I also have a dataFrame name that contains the names corresponding to these numbers.

df:                          
 a   b     c                   name:
 1   val1  val2                  1  cat
 1   val1  val2                  2  dog
 2   val1  val2                  3  rabbit
 3   val1  val2
 3   val1  val2
 3   val1  val2

现在我想用名字替换数字.新的数据帧应如下所示:

Now I want to replace the numbers with the names. The new dataFrame should look like this:

df:                                      
   a        b     c      
   cat      val1  val2                  
   cat      val1  val2                  
   dog      val1  val2                  
   rabbit   val1  val2
   rabbit   val1  val2
   rabbit   val1  val2

我就是这样意识到的.它有效，但我不满足，因为我对名称进行了硬编码...

I realized this like that. It works but I am not content, because I hardCode the names ...

  df$a<-replace(df$a, df$a==1, "cat" )
  df$a<-replace(df$a, df$a==2, "dog" )
  df$a<-replace(df$a, df$a==3, "rabbit" )

如何从数据框名称中获取新值?

How can I get the new values out of my dataframe name ?

谢谢！

推荐答案

示例数据:

df = data.frame(a = c(1,1,2,3,3,3), b = rep('val1', 6), c = rep('val2', 6))
df

#   a    b    c
# 1 1 val1 val2
# 2 1 val1 val2
# 3 2 val1 val2
# 4 3 val1 val2
# 5 3 val1 val2
# 6 3 val1 val2

使用dplyr的recode()，可以实现:

df %>% mutate(a = recode(a, '1' = 'cat', '2' = 'dog', '3' = 'rabbit'))

#        a    b    c
# 1    cat val1 val2
# 2    cat val1 val2
# 3    dog val1 val2
# 4 rabbit val1 val2
# 5 rabbit val1 val2
# 6 rabbit val1 val2

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