使用apply或其他矢量化方法合并列的内容

Question

我有一个几乎完全空白的data.frame,但每行都有一个值.如何使用矢量化或其他r-locald方法将每行的内容合并为一个向量？

样本数据:

raw_data  <- structure(
    list(
        col1 = c("", "", "", "", ""),
        col2 = c("", "", "", "", ""),
        col3 = c("", "", "", "", ""),
        col4 = c("", "", "", "Millburn - Union", ""),
        col5 = c("", "", "Cranston (aka Garden City Center)", "",""),
        col6 = c("", "", "", "", ""),
        col7 = c("", "", "", "", ""),
        col8 = c("", "", "", "", "Colorado Blvd"), 
        col9 = c("", "", "", "", ""),
        col10 = c("", "", "", "", ""),
        col11 = c("Palo Alto",  "Castro (aka Market St)", "", "", "")
    ),
    .Names = c("col1", "col2", "col3", "col4", "col5", "col6", "col7", "col8", "col9", "col10", "col11"),
    row.names = c(5L, 4L, 3L, 2L, 1L),
    class = "data.frame"
)

这是我尝试但它失败了,因为它返回一个二维矩阵而不是所需的向量:

raw_data$test <-  apply(raw_data, MAR=1, FUN=paste0)

Answer 1

您可以使用单个索引操作非常简单地执行此操作:

raw_data[raw_data!='']

演示:

R> raw_data[raw_data!=''];
[1] "Millburn - Union"                  "Cranston (aka Garden City Center)" "Colorado Blvd"                     "Palo Alto"                         "Castro (aka Market St)"

如果您关心矢量顺序是从上到下(而不是从左到右,然后从上到下,这就是上面的操作),您可以转置输入data.frame:

R> t(raw_data)[t(raw_data)!=''];
[1] "Palo Alto"                         "Castro (aka Market St)"            "Cranston (aka Garden City Center)" "Millburn - Union"                  "Colorado Blvd"

Answer 2

你的直觉apply是正确的。您只需将collapse参数传递给paste：

 apply( raw_data, 1, paste0, collapse = "" )
                                  5                                   4                                   3 
                        "Palo Alto"            "Castro (aka Market St)" "Cranston (aka Garden City Center)" 
                                  2                                   1 
                 "Millburn - Union"                     "Colorado Blvd"