合并两个具有不同大小和缺失值的数据框 [英] Merging two data frames with different sizes and missing values

问题描述

在合并R中的两个数据帧时遇到问题.

I'm having a problem merging two data frames in R.

第一个变量包含6个变量的103731 obs.我必须用于合并的变量具有77111个唯一值，其余为NA s，其值为0.第二个变量包含这些变量的频率加上NA s的频率，因此为77112的帧obs 2个变量.

The first one consists of 103731 obs of 6 variables. The variable that I have to use to merge has 77111 unique values and the rest are NAs with a value of 0. The second one contains the frequency of those variables plus the frequency of the NAs so a frame of 77112 obs for 2 variables.

我需要得到的结果帧是第一个与合并变量频率相关联的帧，因此对于合并变量的每个值，其df为103731 obs(因此，如果freq> 1则重复，并且对于每个NA(或0)).

The resulting frame I need to get is the first one joined with the frequency for the merging variable, so a df of 103731 obs with the frequency for each value of the merging variable (so with duplicates if freq > 1 and also for each NA (or 0)).

有人可以帮助我吗?

我现在得到的结果包含一个1 894 919 obs的数据框，并且我使用了:

The result I'm getting now contains a data frame of 1 894 919 obs and I used:

tot = merge(df1, df2, by = "mergingVar", all= F, sort = F);  

我也经常在'all='上打过球，但所有的变体都没有赋予正确的df.

Also I played a lot with 'all=' and none of the variations gave the right df.

推荐答案

为什么不只使用第一个表的频率表?

why don't you just take the frequency table of your first table?

a <- data.frame(a = c(NA, NA, 2,2,3,3,3))
data.frame(table(a, useNA = 'ifany'))

     a Freq
1    2    2
2    3    3
3 <NA>    2

或plyr来自plyr

ddply(a, .(a), mutate, freq = length(a))

   a freq
1  2    2
2  2    2
3  3    3
4  3    3
5  3    3
6 NA    2
7 NA    2

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