在数据框的每一列中最频繁 [英] Most frequent in each column in dataframe

问题描述

如果您想要为数据框中的每个列找到最大频率并返回因子，类别和频率，您该怎么做？ 所以我有代码如下：

  dfreqcommon = data.frame（）
 
 for（i in 1：ncol （钻石））{
 
 dfc = data.frame（t（表格（钻石[，i]）））
 dfc $ Var1 =名称（钻石）[i] 
 
 dfreqcommon = rbind（dfreqcommon，dfc）
 
} 
 
名称（dfreqcommon）= c（因素，类别，频率）
 
 dfreqcommon 
  

但是，这似乎会返回所有因素，类别和频率。我只是想要每个因素的最大频率，并获得它的类别。我尝试将dfc改为

  dfc = data.frame（max（t（table（diamonds [，i]））） ）
  

但它没有显示类别。有什么方法可以解决这个问题吗？

另一种方法是用 base R：

  library（ggplot2）＃仅用于获取钻石data.frame 
 
数据。框架（因素= colnames（菱形），
t（sapply（菱形），＃对每列应用以下函数
函数（x）{
 t_x<  -  sort = TRUE）＃获取频率并按降序排序
 list（Categories = names（t_x）[1]，＃频率最高的值的名称
 Frequency = t_x [1]）＃最高频率
}）））
＃因素类别频率
 #carat克拉0.3 2604 
＃剪切理想21551 
 #color color G 11292 
 #clarity清晰度SI1 13065 
＃深度深度62 2239 
＃表格56 98 81 
 #price price 605 132 
 #xx 4.37 448 
 #yy 4.34 437 
 #zz 2.7 767 
  

What do you do if you wanted to find the maximum frequency for each columns in a dataframe and return the factors, categories, and frequency?

So I have the code as follows:

dfreqcommon = data.frame()

for (i in 1:ncol(diamonds)){

dfc = data.frame(t(table(diamonds[,i])))
dfc$Var1 = names(diamonds)[i]

dfreqcommon = rbind(dfreqcommon, dfc)

}

names(dfreqcommon) = c("Factors","Categories","Frequency")

dfreqcommon

But this seemed to return all factors, categories, and frequency. I just wanted the maximum frequency for each factors and get its categories as well. I tried to change dfc to

dfc = data.frame(max(t(table(diamonds[,i]))))

But it doesn't show the categories. Is there any way to fix this?

解决方案

Another way, with base R:

library(ggplot2) # only to get the diamonds data.frame

data.frame(Factors=colnames(diamonds), 
           t(sapply(diamonds, # apply following function to each column
                    function(x) {
                        t_x <- sort(table(x), decreasing=TRUE) # get the frequencies and sort them in decreasing order
                        list(Categories=names(t_x)[1], # name of the value with highest frequency
                             Frequency=t_x[1]) # highest frequency
                    })))
#        Factors Categories Frequency
#carat     carat        0.3      2604
#cut         cut      Ideal     21551
#color     color          G     11292
#clarity clarity        SI1     13065
#depth     depth         62      2239
#table     table         56      9881
#price     price        605       132
#x             x       4.37       448
#y             y       4.34       437
#z             z        2.7       767

这篇关于在数据框的每一列中最频繁的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！