将多列粘贴在一起 [英] Paste multiple columns together

问题描述

我在数据框中有一堆列，我想将它们粘贴在一起(用-"分隔)，如下所示:

I have a bunch of columns in a dataframe which I want to paste together (seperated by "-") as follows:

data <- data.frame('a' = 1:3, 
                   'b' = c('a','b','c'), 
                   'c' = c('d', 'e', 'f'), 
                   'd' = c('g', 'h', 'i'))
i.e.     
     a   b   c  d  
     1   a   d   g  
     2   b   e   h  
     3   c   f   i  

我想成为谁:

a x  
1 a-d-g  
2 b-e-h  
3 c-f-i  

我通常可以这样:

within(data, x <- paste(b,c,d,sep='-'))

，然后删除旧的列，但是不幸的是，我不知道这些列的名称，只是所有列的统称，例如我会知道cols <- c('b','c','d')

and then removing the old columns, but unfortunately I do not know the names of the columns specifically, only a collective name for all of the columns, e.g. I would know that cols <- c('b','c','d')

有人知道这样做的方法吗?

Does anyone know a way of doing this?

推荐答案

# your starting data..
data <- data.frame('a' = 1:3, 'b' = c('a','b','c'), 'c' = c('d', 'e', 'f'), 'd' = c('g', 'h', 'i')) 

# columns to paste together
cols <- c( 'b' , 'c' , 'd' )

# create a new column `x` with the three columns collapsed together
data$x <- apply( data[ , cols ] , 1 , paste , collapse = "-" )

# remove the unnecessary columns
data <- data[ , !( names( data ) %in% cols ) ]

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