合并data.frames以求和R中相同列的值 [英] Combine data.frames summing up values of identical columns in R

问题描述

我在站点内有3个数据框(行:站点，列:物种名称).行号相同，但列号不同，因为在所有三个数据帧中并非所有种类都相同.我想将它们合并到一个数据框中，并总结出大量相同的物种.例如:

I have 3 data frames (rows: sites, columns:species name) of species abundances within sites. Row numbers are identical, but column numbers differ as not all species are in all three data frames. I would like to merge them into one data frame with abundances of identical species summed up. For example:

data.frame1

data.frame1

       Sp1  Sp2  Sp3  Sp4
site1   1    2    3    1
site2   0    2    0    1
site3   1    1    1    1

data.frame2

data.frame2

       Sp1  Sp2  Sp4
 site1  0    1    2
 site2  1    2    0
 site3  1    1    1

data.frame3

data.frame3

       Sp1  Sp2  Sp5  Sp6
 site1  0    1    1    1     
 site2  1    1    1    5
 site3  2    0    0    0

我想要的东西是这样的:

What I want to have is something like:

       Sp1  Sp2  Sp3  Sp4  Sp5  Sp6
 site1  1    4    3    3    1    1
 site2  2    5    0    1    1    5
 site3  4    2    1    2    0    0

我想我必须使用合并，但是到目前为止，我的尝试未能获得我想要的.

I guess i'd have to work with merge, but so far my attempts have failed to get what I want.

感谢您的帮助.

推荐答案

我会这样使用plyr的rbind.fill:

pp <- cbind(names=c(rownames(df1), rownames(df2), rownames(df3)), 
                        rbind.fill(list(df1, df2, df3)))

#   names Sp1 Sp2 Sp3 Sp4 Sp5 Sp6
# 1 site1   1   2   3   1  NA  NA
# 2 site2   0   2   0   1  NA  NA
# 3 site3   1   1   1   1  NA  NA
# 4 site1   0   1  NA   2  NA  NA
# 5 site2   1   2  NA   0  NA  NA
# 6 site3   1   1  NA   1  NA  NA
# 7 site1   0   1  NA  NA   1   1
# 8 site2   1   1  NA  NA   1   5
# 9 site3   2   0  NA  NA   0   0

然后，与plyr's ddply进行聚合，如下所示:

Then, aggregate with plyr's ddply as follows:

ddply(pp, .(names), function(x) colSums(x[,-1], na.rm = TRUE))
#   names Sp1 Sp2 Sp3 Sp4 Sp5 Sp6
# 1 site1   1   4   3   3   1   1
# 2 site2   2   5   0   1   1   5
# 3 site3   4   2   1   2   0   0

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