Question

我有一个关于保存长度不等的数据帧的问题。是否可以在不引入NA的情况下保存具有可变长度的表格？这是NA的一个例子，但这不是我想要保存的。

x <- list(matrix(c(1,4,3,2), ncol = 2,                   
dimnames = list(c("A","B"), NULL)),            
matrix(c(23,9,4,4,22,54), ncol = 2,                   
dimnames = list(c("C","D","E"), NULL))) 

out <- lapply(x, rownames) 
foo <- function(x, max, repl = NA) {     
if(length(x) == max)         
out <- x     
else {         
out <- rep(repl, max)         
out[seq_along(x)] <- x     
}     
out 
} 
out <- lapply(out, foo, max = max(sapply(out, length))) 
(out <- do.call(rbind, out))

谢谢

Answer 1

我会创建一个列表并使用write写入文件。还有其他可能性（请参阅?write的帮助文件）。

myl <- list(a = letters[1:10], b = 1:3, c = "kaplah") #create some data

# for every element in the list (`myl`), write that element to a file
# and append if necessary. also, if list element is a character, write
# to as many columns as there are characters.
lapply(X = myl, FUN = function(x) {
    write(x, append = T, file = "test.txt", ncolumns = length(x))
})

结果是

a b c d e f g h i j
1 2 3
kaplah

Answer 2

数据框必须是矩形的。如果要存储可变长度数据，则需要使用列表。

您希望将数据存储在数据框中的数据是什么？

在不引入NA的情况下以不等长度保存数据

2 个答案: