Emer Emer - 3 months ago 12
R Question

Printing dataframes with long strings in R

Let's have a dataframe with long strings in one column:

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


How could I print the dataframe without showing the entire string?
Something like this:

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

You can redefine the print.data.frame method, and in this function use substr to trim your character vectors to the desired maximum length:

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)
}

Create data. Note my addition of stringsAsFactors=FALSE:

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

Print 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