Printing dataframes with long strings in R

Question

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)),collaps         


        

Answer 1

This is one way:

within(df, {
    long = paste(substr(long, 1, 10), "...", sep = "")
})

I use substr to get the first part of the string, than I use paste for the "...". To permanently change the characters in df, simply do:

df = within(df, {
    long = paste(substr(long, 1, 10), "...", sep = "")
})

Answer 2

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

Answer 3

Uses dplyr and prints out a modified version of the original data frame (without changing it). Only shortens values which exceed specified length:

library(dplyr)

print.data.frame(df %>% mutate(long = ifelse(
    nchar(long > 11),
    paste0(substr(long, 1, 8), "..."),
    long
)))