r - 在 R 中打印长字符串数据帧

Question

让我们有一列包含长字符串的数据框:

 df<-data.frame(short=rnorm(10,0,1),long=replicate(10,paste(rep(sample(letters),runif(1,5,8)),collapse="")))

如何打印数据框而不显示整个字符串？像这样的事情:

        short        long
1   0.2492880 ghtaprfv...
2   1.0168434 zrbjxvci...
3   0.2460422 yaghkdul...
4   0.1741522 zuabgxpt...
5  -1.1344230 mzhjtwcr...
6  -0.7104683 fcbhuegt...
7   0.2749227 aqyezhbl...
8  -0.4395554 azecsbnk...
9   2.2837716 lkgwzedf...
10  0.7695538 omiewuyn...

Answer 1

您可以重新定义 print.data.frame 方法，并在此函数中使用 substr 将字符向量修剪为所需的最大长度:

print.data.frame <- function (x, ..., maxchar=20, digits = NULL, quote = FALSE,
    right = TRUE, row.names = TRUE) 
{
  x <- as.data.frame(
      lapply(x, function(xx)
            if(is.character(xx)) substr(xx, 1, maxchar) else xx)
  )
  base::print.data.frame(x, ..., digits=digits, quote=quote, right=right, 
      row.names=row.names)
}

创建数据。请注意我添加的 stringsAsFactors=FALSE:

df <- data.frame(
    short=rnorm(10,0,1),
    long=replicate(10,paste(rep(sample(letters),runif(1,5,8)),collapse="")),
    stringsAsFactors=FALSE
)

打印data.frame:

print(df, maxchar=10)
        short       long
1  -0.6188273 cpfhnjmeiw
2  -0.0570548 bwcmpinedr
3  -0.5795637 dcevnyihlj
4   0.1977156 qzxlhvnarm
5  -1.9551196 aiflwtkjdq
6  -1.2429173 vlscerwhgq
7  -0.5897045 fziogkpsyr
8   0.4946985 pdeswloxcn
9   0.3262543 kxlofchszd
10 -1.8059621 wncaedpzty